JP5528264B2 - Cutting tool and method of cutting work material using cutting tool - Google Patents

Description

  The present invention relates to a cutting tool and a cutting method of a work material using the cutting tool.

  For cutting tools, particularly cutting tools for parting and grooving, it has been studied to suppress lateral displacement of the installed cutting insert. For example, Patent Literature 1 discloses a cutting insert provided with holder mounting engagement surfaces on the upper surface side and the bottom surface side. The mounting engagement surface on the upper surface side of the cutting insert is a V-projection whose transverse section has an apex angle, and the mounting engagement surface on the bottom surface side has a V-groove whose lateral section has an apex angle. Due to the V groove and the V protrusion, the displacement of the cutting insert in the left-right direction is suppressed.

Japanese Utility Model Publication No. 1-149204

  However, even in a cutting tool using such a cutting insert, for example, when performing end surface grooving to form an annular groove on the end surface of the work material, due to differences in the processing diameter on the left and right of the cutting edge, Since the cutting speed is different, a torsional moment acts on the cutting edge portion, and the cutting insert may be easily displaced from side to side.

  An object of the present invention is to provide a cutting tool suitable for parting off and grooving, particularly end face grooving.

  The cutting tool of the present invention includes a cutting insert having a cutting edge, a holder having an upper jaw portion and a lower jaw portion, each of which has an insert contact portion that sandwiches the cutting insert at a tip portion and contacts the cutting insert. The insert contact portion of the lower jaw portion has a first contact surface and a second contact surface that are inclined upward from the respective end portions toward the center portion in the front end view. The angle formed by the first contact surface and the second contact surface is the smallest at the tip of the insert contact portion.

  Moreover, the cutting tool of the present invention has a cutting insert having a cutting edge, and an upper jaw portion and a lower jaw portion each having an insert contact portion that sandwiches the cutting insert at a tip portion and contacts the cutting insert. A cutting tool comprising a holder, wherein the insert contact portion of the lower jaw portion includes a first contact surface and a second contact surface that are inclined downward from the respective end portions toward the center portion in a front end view. And the angle formed by the first contact surface and the second contact surface is the smallest at the tip of the insert contact portion.

  The method for cutting a work material according to the present invention includes a step of rotating the work material, a step of bringing the cutting tool close to the rotating work material, and the cutting of the rotating work material. A step of contacting the cutting edge of the tool to cut the workpiece, and a step of separating the cutting tool from the cut workpiece.

According to the cutting tool of the present invention, the insert contact portion of the lower jaw portion has the first contact surface and the second contact surface that are inclined upward or downward from the respective end portions toward the central portion in the front end view. The angle formed by the first contact surface and the second contact surface is the smallest at the tip of the insert contact portion. Therefore, especially in the end surface grooving process in which an annular groove is formed on the end surface of the work material, the first contact surface and the second contact surface receive the force acting in the lateral direction of the cutting insert by the torsional moment of the cutting blade. This suppresses the displacement in the left-right direction.

It is a perspective view which shows the example of embodiment of the cutting tool of this invention. (A) is a side view of the cutting tool shown in FIG. 1, (b) is a side view of the holder used for the cutting tool shown in FIG. 2 (a). (A) is a front end view of the holder shown in FIG. 2 (b), and (b) is a partially enlarged view of FIG. 3 (a). (A) is sectional drawing in the AA line of the lower jaw part of the holder shown in FIG.2 (b), (b) is sectional drawing in the BB line of FIG.2 (b), (c) These are sectional drawings in the CC line of Drawing 2 (b). It is a perspective view of the cutting insert used for the cutting tool shown in FIG. (A)-(c) is the schematic which shows an example of the cutting method of the workpiece of this invention, (d) is a perspective view of the processed workpiece.

<Cutting tools>
Hereinafter, the example of embodiment of the cutting tool of this invention is described in detail using FIGS. The cutting tool of the present invention can be applied to any of grooving of the inner diameter, grooving of the outer diameter, parting off, and end face grooving. In this example, the case where it is applied for end face grooving will be described as an example.

  As shown in FIGS. 1 and 2 (a), a cutting tool 20 includes a cutting insert 1 having a cutting edge 5 (hereinafter, simply referred to as the insert 1) and a holder 100 that holds the cutting insert 1 at the tip. And. The holder 100 has an upper jaw portion 101 and a lower jaw portion 102 that sandwich the insert 1. The upper jaw 101 is at a higher position than the lower jaw 102. The insert 1 is sandwiched so that the cutting blade 5 protrudes from the tip of the upper jaw portion 101.

  As shown in FIG. 2B, the holder 100 has an upper jaw portion 101 and a lower jaw portion 102 each having an insert contact portion 103 that contacts the insert 1. Specifically, the upper jaw portion 101 has an insert contact portion 103a, and the lower jaw portion 102 has an insert contact portion 103b.

  As shown in FIG. 3, the insert contact portion 103 a is inclined downward from the respective end portions toward the central portion in the front end view. With this configuration, the displacement of the insert 1 in the left-right direction can be suppressed.

The insert contact portion 103b has a first contact surface 104a and a second contact surface 104b that are inclined upward from the respective end portions toward the center portion when viewed from the front end. In this example, as shown in FIG. 3B, the first contact surface 104a and the second contact surface 104b are located above the straight line L connecting the end portions of the insert contact portion 103b in the front end view. Inclined so as to intersect on a perpendicular bisector (not shown) of the straight line L to form a convex shape. With this configuration, it is possible to receive a force applied in the left-right direction of the insert 1 at the time of cutting, and the insert 1 can suppress displacement in the left-right direction. Moreover, it can also suppress that a crack arises in the insert 1. In addition, in this example, although the 1st contact surface 104a and the 2nd contact surface 104b showed the aspect inclined upwards, according to the bottom face shape of the insert 1, you may incline below.

  In this example, the angle α formed by the first contact surface 104a and the second contact surface 104b at the distal end portion of the insert contact portion 103b is the smallest at the distal end of the insert contact portion 103b. Specifically, when the angles formed by the first contact surface 104a and the second contact surface 104b shown in FIGS. 4A to 4C are α1, α2, and α3, respectively, α1 <α3 <α2. With this configuration, when cutting, the force can be effectively received by the first contact surface 104a and the second contact surface 104b at the distal end portion of the insert contact portion 103b that receives the force in the horizontal direction most strongly. Therefore, the position shift of the insert 1 in the left-right direction can be suppressed.

  Note that the angle α is preferably in the range of 90 ° to 140 ° from the viewpoint of maintaining the strength of the insert 1 and the holder 100. In this example, as shown in FIG. 4, α1 = 134 ° 15 ′, α2 = 138 ° 48 ′, and α3 = 136 ° 30 ′.

  Regarding the angle α of the insert contact portion 103b, there is no particular limitation on the relationship in size between the center portion and the rear end portion. However, from the viewpoint of improving the binding force of the insert, the angle α at the rear end portion of the insert contact portion 103b. Is preferably the largest. Further, the change in the magnitude of the angle α may be linear or non-linear. Further, the shapes of the first contact surface 104a and the second contact surface 104b are not particularly limited, and the first contact surface 104a and the second contact surface 104b are curved surfaces from the viewpoint of better stress distribution. There may be. In this case, as the magnitude of the angle α, the first contact surface 104a and the second contact shown as curves in a cross section in a direction parallel to the straight line L and intersecting the first contact surface 104a and the second contact surface 104b. What is necessary is just to measure the angle which each tangent of the surface 104b makes and to make into an angle (alpha). In addition, in order to suppress that a crack arises in the insert 1, as shown in FIG.4 (b), you may have the top surface 104c between the 1st contact surface 104a and the 2nd contact surface 104b. In this case, an angle formed by a virtual extension line between the first contact surface 104a and the second contact surface 104b may be measured to obtain an angle α.

  In addition, the angle α is preferably gradually increased from the front end to the rear end of the insert contact portion 103b. With this configuration, the stress distribution can be improved and the strength of the insert 1 and the holder 100 can be maintained. From the viewpoint of maintaining the strength of the insert 1 and the holder 100, the difference between the maximum value and the minimum value of the angle α is preferably 5 ° to 10 °.

  In this example, as shown in FIG. 4, the relationship between the width Wa of the first contact surface 104a and the width Wb of the second contact surface 104b is Wa ≧ Wb. With this configuration, it is possible to stably restrain the insert 1 and suppress a positional shift in the left-right direction.

  When used for end face grooving, the first contact surface 104a is located closer to the center of rotation of the work material 30 than the second contact surface 104b in the front end view of the insert contact portion 103b. The width Wa of the first contact surface 104a is preferably larger than the width Wb of the second contact surface 104b.

In the end face grooving, under cutting conditions with a higher load, the edge of the cutting edge closer to the center of rotation of the work material, that is, the inner edge of the working groove, and the other cutting edge are covered. The difference in cutting resistance received by the end located on the side farther from the center of rotation of the cutting material, that is, on the outer peripheral side of the machining groove, is increased. Specifically, the cutting resistance is higher on the inner peripheral side where the cutting speed is lower, and the cutting resistance is lower on the outer peripheral side where the cutting speed is higher. Therefore, by adjusting the width of the first contact surface 104a located on the side close to the rotation center of the work material 30 to be larger than the width of the second contact surface 104b, the balance of the force applied in the left-right direction is adjusted, and the insert 1 can be more reliably suppressed. Here, as shown in FIG. 4, the width is the length of the first contact surface 104a and the second contact surface 104b shown as straight lines when viewed from the front end. When the first contact surface 104a and the second contact surface 104b are curved surfaces, the first contact shown as a curve in a cross section parallel to the straight line L and intersecting the first contact surface 104a and the second contact surface 104b. What is necessary is just to measure the arc length of the surface 104a and the 2nd contact surface 104b.

  Although the insert contact portion 103b of the lower jaw portion 102 has been described in detail, the shape of the insert contact portion 103b is formed on the insert contact portion 103a of the upper jaw portion 101 in order to better suppress the displacement of the insert 1 in the left-right direction. May be applied.

  Further, in this example, as shown in FIG. 4, the lower jaw portion 102 is curved along the outer periphery of the machining groove in the front end view. When the lower jaw portion 102 is formed vertically in the front end view, an end surface grooving process forms an annular groove, so that the lower jaw portion 102 comes into contact with the machining groove during machining. The depth is limited to the distance from the cutting blade 5 to the lower jaw 102. Therefore, the machining diameter is determined in advance, and the lower jaw 102 is curved along the outer periphery of the machining groove.

  Furthermore, in this example, as shown in FIG. 4, a chamfered portion 104 d is provided at the intersection between the first contact surface 104 a located on the inner peripheral side of the machining groove and the lower jaw portion 102. At the time of cutting, the tip of the cutting insert 1 is pressed from above, so that a stronger stress is more easily applied to the lower jaw portion 102 than to the upper jaw portion 101. With this configuration, the thickness of the lower jaw can be increased and the strength of the holder can be increased.

  In addition, since the annular groove is processed, chips are more easily introduced on the inner diameter side than on the outer diameter side at the contact portion between the insert 1 and the holder 100. Therefore, by providing the chamfered portion 104d, the chips can flow toward the lower end portion of the lower jaw portion 102.

  As shown in FIG. 2, a shank portion 105 is formed on the rear end side with respect to the upper jaw portion 101 and the lower jaw portion 102. Further, the holder 100 of this example is formed with a screw hole 107 for inserting the clamp screw 106 from the upper jaw portion 101 to the lower jaw portion 102.

  Moreover, when especially high durability is calculated | required in the holder 100 whole, it is preferable that the upper jaw part 101, the lower jaw part 102, and the shank part 105 are integrally molded. Since these are integrally molded, no joint surfaces are formed between the upper jaw portion 101 and the shank portion 105 and between the lower jaw portion 101 and the shank portion 105, so that the rigidity of the cutting tool 20 can be further increased.

In order to reduce the cost of the cutting tool 20 while obtaining the effects of the present invention, it is also effective that the material of the lower jaw portion 102 is higher in rigidity than the material of the upper jaw portion 101 and the shank portion 105. When the cutting tool 20 is used, the tip of the cutting insert 1 is pressed from above, so that a stronger stress is more easily applied to the lower jaw part 102 than to the upper jaw part 101 or the shank part 105. Since a material with high rigidity is expensive or requires a high level of technology for processing, a high rigidity material is used for the lower jaw part 102 which is subjected to relatively large stress, and the upper jaw part having a small comparative adaptability. 101 and the shank part 15 are made of a material that is less rigid and easy to process than the lower jaw part 102,
The cutting tool 20 with high durability and low cost can be manufactured.

  As shown in FIGS. 1 and 2, the holder 100 is preferably provided with a slit 109 on the rear end side of the upper jaw portion 101 and the lower jaw portion 102. Since the upper jaw portion 101 or the lower jaw portion 102 is more easily elastically deformed by the slit 109, the cutting insert 1 can be easily attached to and detached from the holder 100.

  In addition, the lower jaw portion 102 is formed with an abutting portion 108 that is brought into contact with the side surface on the rear end side of the insert 1 for positioning. In this case, it is particularly preferable that the slit 109 is formed above the contact surface 108. When the slit 109 is formed above the contact portion 108, the thickness of the holder 100 below the slit 109 is made larger than when the slit 109 is formed below the lower jaw portion of the contact surface 108. be able to.

  As shown in FIG. 5, in this example, the insert 1 has a substantially prismatic shape, is located between the cutting part I and the cutting part I at both ends, and is fixed by the holder 100 to the upper jaw part 101. And a clamp part II having clamp surfaces 21 and 31 in contact with the lower jaw part 102.

  Further, the cutting part I has a rectangular shape having two long sides and two short sides in plan view, and has an upper surface 2, a lower surface 3, and an upper surface 2 and a side surface 4 connected to the lower surface 3. . The upper surface 2 functions as a rake surface, the lower surface 3 functions as a mounting surface for mounting on the holder, and the side surface 4 functions as a flank surface. Moreover, in this example, the length of the longitudinal direction of the insert 1 is 20 mm, and the length of the width direction perpendicular | vertical to a longitudinal direction is 3-6 mm in planar view. This width becomes smaller as it approaches the clamp part II so that the insert does not interfere with the inner wall surface of the groove machined into the work material during machining. The height from the lower surface 3 to the upper surface 2 of the insert 1 is set to 4 to 6 mm according to the length of the insert 1 in the width direction.

  A cutting edge 5 is provided at the intersection of the upper surface 2 and the side surface 4. The cutting blade 5 is provided, for example, along the intersecting portion in the longitudinal direction and the width direction of the cutting portion I. The shape of the cutting blade 5 is not particularly limited, such as a linear shape or an arc shape.

  Further, the clamp part II is provided with a clamp surface 21 on the upper side and a clamp surface 31 on the lower side, and has a shape that fits into the insert contact parts 103a and 103b of the upper jaw part 101 and lower jaw part 102 of the holder 100, respectively. It is preferable. By having such clamp surfaces 21 and 31, the position of the insert 1 is stabilized, the positioning accuracy can be further increased, and the restraining force can be increased.

  In particular, as shown in FIG. 5, the clamp surfaces 21 and 31 have a concave shape, and as shown in FIG. 3, the insert contact portions 103 a 103 b respectively formed on the upper jaw portion 101 and the lower jaw portion 102 have a convex shape. preferable. With this configuration, the possibility of cracks occurring in the insert 1 can be further suppressed.

Examples of the material of the cutting insert 1 include cemented carbide or cermet. As the composition of the cemented carbide, for example, WC-Co produced by adding cobalt (Co) powder to tungsten carbide (WC) and sintering, and WC-Co obtained by adding titanium carbide (TiC) to WC-Co. There is WC-TiC-TaC-Co in which tantalum carbide (TaC) is added to TiC-Co and WC-TiC-Co. The cermet is a sintered composite material in which a metal is combined with a ceramic component, and specifically includes a titanium compound mainly composed of titanium carbide (TiC) and titanium nitride (TiN).

The surface of the cutting insert 1 may be coated with a film using a chemical vapor deposition (CVD) method or a physical vapor deposition (PVD) method. Examples of the composition of the coating include titanium carbide (TiC), titanium nitride (TiN), titanium carbonitride (TiCN), and alumina (Al ₂ O ₃ ).

  The insert 1 can be fixed to the holder 100 as follows, for example. As shown in FIG. 1 and FIG. 2A, first, the cutting insert 1 is inserted between the upper jaw portion 101 and the lower jaw portion 102 along the insert contact portions 103a and 103b, The end side surface 4 is pressed against the contact portion 108.

  Next, the clamp screw 106 is tightened, and the upper jaw portion 101 is elastically deformed and pushed down. As a result, the insert 1 is pressed against the lower jaw 102 and is sandwiched and fixed between the upper jaw 101 and the lower jaw 102. Further, when the slit 109 is formed, the upper jaw portion 101 is more easily elastically deformed by the slit 109, so that the tip of the upper jaw portion 102 can be pushed down more easily.

  In the cutting insert 1, the cutting part I is preferably provided in pairs at both ends of the clamp part II. Accordingly, the insert 1 is provided with a plurality of cutting blades 5, and even when the cutting blade 5 is worn for a long time, another cutting blade 5 that is not worn can be used. Since it is not necessary to prepare the insert 1, it is economical. For example, in the cutting tool 20 of the present embodiment, when one of the cutting blades 5 is worn, the insert 1 is removed from the cutting tool 20, and the other cutting part I of the cutting part I of the insert 1 is replaced. What is necessary is just to attach to the cutting tool 20 again. Thereby, the cutting blade 5 which is not worn can be positioned outside the holder 100 and used for cutting.

<Cutting method of work material>
Hereinafter, an example of a cutting method of a work material performed using the cutting tool 20 of the present invention will be described with reference to FIG. Since this example is an end face grooving process, as shown in FIG. 6D, an annular groove 31 is formed on the end face of the work material. Note that a part of the work material shown in FIGS. 6A to 6C is shown in cross-sectional view.

The cutting method of the work material performed using the cutting tool 20 includes the following steps (i) to (iv).
(I) A step of rotating the work material 30 in the direction of arrow D as shown in FIG.
(Ii) A step of moving the cutting tool 20 in the direction of arrow E to bring the cutting tool 20 close to the rotating work material 30.
(Iii) A step of cutting the workpiece 30 by bringing the cutting blade 5 of the cutting tool 20 into contact with the rotating workpiece 30 as shown in FIG.
(Iv) A step of moving the cutting tool 20 in the direction of arrow F and separating the cutting tool 20 from the cut workpiece 30 as shown in FIG.

  In the step (i), the work material 30 and the cutting tool 20 may be relatively close to each other. For example, the work material 30 may be close to the cutting tool 20. Similarly, in the step (iv), the work material 30 and the cutting tool 20 need only be relatively distant from each other. For example, the work material 30 may be kept away from the cutting tool 20. Further, in the step (iii), in the grooving process, a longitudinal feed process for forming the groove is performed and a lateral feed process for flattening the bottom surface of the groove is performed. In the case of continuing the cutting process, the process of bringing the cutting blade 5 of the cutting tool 20 into contact with a different part of the work material 30 may be repeated while maintaining the state where the work material 30 is rotated.

  Further, representative examples of the material of the work material include carbon steel, alloy steel, stainless steel, cast iron, and non-ferrous metal.

  In this example, a left-handed holder has been described, but a right-handed holder may be used.

DESCRIPTION OF SYMBOLS 1 Cutting insert 2 Upper surface 21 Clamp surface 3 Lower surface 31 Clamp surface 4 Side surface 5 Cutting blade 100 Holder 101 Upper jaw part 102 Lower jaw part 103 Insert contact part 103a Upper jaw part insert contact part 103b Lower jaw part insert contact part 104 Contact surface 104a 1st Contact surface 104b Second contact surface 104c Top surface 104d Chamfered portion 105 Shank portion 106 Clamp screw 107 Screw hole 108 Abutting portion 109 Slit 20 Cutting tool 30 Work material 31 Annular groove

Claims (6)

A cutting tool comprising: a cutting insert having a cutting edge; and a holder having an upper jaw portion and a lower jaw portion, each having an insert contact portion that sandwiches the cutting insert at a tip portion and contacts the cutting insert. ,
The insert contact portion of the lower jaw portion has a first contact surface and a second contact surface that are inclined upward from the respective end portions toward the center portion in a front end view,
An angle formed between the first contact surface and the second contact surface is the smallest at the tip of the insert contact portion. A cutting tool comprising: a cutting insert having a cutting edge; and a holder having an upper jaw portion and a lower jaw portion, each having an insert contact portion that sandwiches the cutting insert at a tip portion and contacts the cutting insert. ,
The insert contact portion of the lower jaw portion has a first contact surface and a second contact surface that are inclined downward from the respective end portions toward the center portion in a front end view,
An angle formed between the first contact surface and the second contact surface is the smallest at the tip of the insert contact portion.   The cutting tool according to claim 1 or 2, wherein an angle formed by the first contact surface and the second contact surface is increased from a front end to a rear end of the insert contact portion.   The cutting tool according to claim 3, wherein a difference between a maximum value and a minimum value of an angle formed by the first contact surface and the second contact surface is 5 ° to 10 °. The cutting tool is a turning tool used to form an annular groove on an end surface of a rotating work material,
In the front end view of the insert contact portion, the first contact surface is located closer to the rotation center of the work material than the second contact surface,
The cutting tool according to any one of claims 1 to 4, wherein a width of the first contact surface is larger than a width of the second contact surface. A method of cutting a work material using the cutting tool according to any one of claims 1 to 5,
Rotating the work material;
Bringing the cutting tool close to the rotating work material;
Cutting the work material by bringing the cutting edge of the cutting tool into contact with the rotating work material;
And a step of separating the cutting tool from the cut work material.

Images