JP7645174B2 - Cutting tool and method for manufacturing machined product - Google Patents

Description

The present disclosure relates to a cutting tool and a method for manufacturing a machined product. One example of a cutting tool is a so-called turning tool (milling tool). The turning tool can be used for turning processes such as face milling and end milling.

For example, the milling tools described in Patent Documents 1 and 2 are known as cutting tools. In the milling tools described in Patent Documents 1 and 2, a cartridge (cutting blade member) equipped with a cutting blade such as a cutting insert is attached to the tool body. The milling tool described in Patent Document 1 has an attachment groove whose mouth is narrow in the direction of centrifugal force. The cartridge is fastened and fixed to the tool body by this attachment groove and attachment bolt. This makes it possible to prevent the cutting blade tip and components from scattering due to centrifugal force. Also, in the milling tool described in Patent Document 2, the cutting blade member is pressed and fixed against the inner surface of the insertion hole by a clamp screw. This fixes the orientation around the axis within the insertion hole, allowing for stable cutting.

JP 2002-011612 A JP 2002-331412 A

However, in the milling tool described in Patent Document 1, the cartridge is fixed by the mounting bolt only in the direction in which the centrifugal force is applied. Therefore, when a cutting load is applied from the front to the rear in the rotation direction during cutting, so-called chatter vibration may occur. On the other hand, in the milling tool described in Patent Document 2, the cutting blade member is pressed and fixed against the inner surface of the insertion hole by the clamp screw from the front in the rotation direction of the axis. Therefore, it takes time to attach the clamp screw, which may result in a decrease in processing efficiency.

This disclosure was made in consideration of the above problems, and aims to provide a cutting tool that is easy to use and can reduce the occurrence of chatter vibrations during cutting.

A cutting tool according to one aspect of the present disclosure has a main body portion extending from the tip to the rear end along a rotation axis and having a pocket located on the tip side, a cutting part located in the pocket and having a cutting edge located on the tip side, and a fixture for fixing the cutting part to the main body portion. The pocket has a seat surface facing forward in the rotation direction of the rotation axis and a constraint side surface located near the rotation axis relative to the seat surface. The cutting part has a back surface facing the seat surface, an inner surface facing the constraint side surface, a first outer surface located opposite the inner surface, and a second outer surface located on the rear end side of the first outer surface and in contact with the fixture. The back surface has an outer region located on the outer periphery and in contact with the seat surface, and an inner region connected to the inner surface and the outer region and separated from the seat surface.

The above cutting tool is easy to use and reduces the occurrence of chatter vibrations during cutting.

1 is a perspective view showing a cutting tool according to an embodiment; 2 is a plan view of the cutting tool shown in FIG. 1 as viewed from an A1 direction. 2 is a plan view of the cutting tool shown in FIG. 1 as viewed from a direction A2. FIG. 4 is an enlarged view showing a part of a main body according to the embodiment. 2 is an enlarged view showing a main body portion, a first cutting portion, a first fixing tool, and the like in the cutting tool shown in FIG. 1 . 6 is a plan view of the cutting tool shown in FIG. 5 as viewed from a direction A3. FIG. 7 is a perspective view showing the cutting tool shown in FIG. 6 in a state where a first cutting portion is not clamped by a first fastener. 7 is a perspective view showing a state in which a first cutting portion is clamped by a first fastener in the cutting tool shown in FIG. 6 . FIG. FIG. 2 is a perspective view showing a first cutting portion and the like according to the embodiment. 10 is a plan view of the first cutting portion and the like in FIG. 9 as viewed from the A4 direction. 10 is a plan view of the first cutting portion and the like in FIG. 9 as viewed from the A5 direction. FIG. 3 is an enlarged view of the XII-XII cross section shown in FIG. 2 . FIG. 3 is an enlarged view of a cross section taken along line XIII-XIII of FIG. 2 . FIG. 2 is a schematic explanatory diagram showing one step of a method for producing a machined product according to one embodiment. FIG. 2 is a schematic explanatory diagram showing one step of a method for producing a machined product according to one embodiment. FIG. 2 is a schematic explanatory diagram showing one step of a method for producing a machined product according to one embodiment.

The cutting tool 1 of the embodiment will be described in detail below with reference to the drawings. However, for the sake of convenience, each of the drawings referred to below shows a simplified view of only the main components necessary to explain the embodiment. Therefore, the cutting tool 1 of the present disclosure may include any component not shown in each of the drawings referred to. Furthermore, the dimensions of the components in each drawing do not faithfully represent the actual dimensions of the components or the dimensional ratios of each component.

As shown in FIG. 1, the cutting tool 1 according to the embodiment has a rotation axis O1 and is a so-called rotating tool. Examples of rotating tools include milling tools and end mills. The example rotating tool shown in the figure is a milling tool. Note that the rotation axis O1 is the axis about which the cutting tool 1 rotates, and is not a tangible object that the cutting tool 1 has.

As shown in FIG. 1 and other figures, the cutting tool 1 includes a main body 3, a cutting part 5, and a fixing device 7. The main body 3 extends from the tip 3A to the rear end 3B along the rotation axis O1. As shown in FIG. 2, the main body 3 has a pocket 9 located on the tip 3A side. FIG. 2 is a side view of the cutting tool 1 shown in FIG. 1 as seen from the A1 direction. The cutting part 5 is located in the pocket 9 and has a cutting edge 11 located on the tip 3A side. The fixing device 7 is a member used to fix the cutting part 5 to the main body 3, and in the example shown in FIG. 1 and other figures, it is a screw. In the following, unless otherwise specified, the cutting tool 1 is shown in a state in which the cutting part 5 is fastened by the fixing device 7.

The main body 3 is a base portion of the cutting tool 1. There may be only one pocket 9, or there may be multiple pockets 9 as shown in FIG. 3. FIG. 3 is a view of the cutting tool 1 shown in FIG. 1 as viewed from the A2 direction (the tip 3A side). When the main body 3 has multiple pockets 9, one of the multiple pockets 9 is designated as a first pocket 9A. The number of cutting portions 5 is not particularly limited, and may be multiple as shown in FIG. 3. When the main body 3 has multiple pockets 9, the first pocket 9A is designated as a first pocket 9A.
The cutting portion 5 located in the pocket 9A is defined as a first cutting portion 5A. The number of fasteners 7 is not particularly limited, and may be multiple as shown in Fig. 1. When the cutting tool 1 has multiple fasteners 7, the fastener 7 that fastens the first cutting portion 5A to the main body portion 3 is defined as a first fastener 7A. In an example shown in Fig. 5 etc., the first fastener 7A may be a first screw.

The rotation direction O2 is not limited to the direction shown in FIG. 1. For example, if the cutting tool 1 has a configuration that is inverted around the rotation axis O1 with respect to the configuration shown in FIG. 1, the rotation direction O2 may be the opposite direction.

In the example shown in FIG. 1, the cutting tool 1 is disk-shaped and extends from the tip 3A to the rear end 3B along the rotation axis O1. For ease of explanation, the parts of the body 3 located on the tip 3A side and the rear end 3B side may be referred to as the first end 3A and the second end, respectively. As is clear from the fact that the cutting tool 1 has a first pocket 9A, etc., the cutting tool 1 is not strictly disk-shaped. The length of the body 3 in the direction along the rotation axis O1 is, for example, 40 mm to 80 mm. The outer diameter of the body 3 in the direction perpendicular to the rotation axis O1 is, for example, 40 mm to 350 mm.

The main body 3 can rotate around the rotation axis O1. There are no particular limitations on the shape of the main body 3, and it may be, for example, approximately cylindrical or approximately conical, and may have irregularities. The main body 3 may be composed of multiple members, or may be composed of a single member.

As shown in FIG. 6, the first pocket 9A has a seat 13 facing forward in the rotation direction O2 of the rotation axis O1. In other words, the main body 3 has the seat 13. The seat 13 may be located on the first end 3A side of the main body 3. The shape of the seat 13 is not limited to the planar shape shown in FIG. 4, but may be a curved shape or may have uneven portions. Note that FIG. 6 is a view of the cutting tool 1 shown in FIG. 5 as viewed from the A3 direction (the first end 3A side).

The first pocket 9A has a constraint side 15 located near the rotation axis O1 relative to the seat surface 13. In other words, the main body 3 has the constraint side 15. The constraint side 15 may face in a direction away from the rotation axis O1, i.e., toward the outer periphery. The shape of the constraint side 15 is not particularly limited, and may be flat or curved, and may have uneven portions.

The first cutting section 5A located in the first pocket 9A has a cutting edge 11 located on the side of the first end 3A. A machined product can be manufactured by cutting the workpiece using this cutting edge 11. The first cutting section 5A may be composed of multiple members or may be composed of a single member. In the example shown in Figure 5, the first cutting section 5A has a cutting insert 17 and a cartridge 19.

In the example shown in FIG. 5, the cutting insert 17 has a cutting edge 11. The cutting edge 11 is located forward of the rotation direction O2 of the cutting insert 17 and on the side of the first end 3A. The cutting edge 11 does not have to be located only in this portion. For example, when the cutting edge 11 located forward of the rotation direction O2 of the cutting insert 17 and on the side of the first end 3A is defined as the first cutting edge 21, the cutting insert 17 may further have a second cutting edge 23 located forward of the rotation direction O2 of the cutting insert 17 and on the outer periphery side. In the example shown in FIG. 5, the first cutting edge 21 and the second cutting edge 23 are located on the outer periphery side of the cutting insert 17. The first cutting edge 21 and the second cutting edge 23 are not limited to a straight shape as shown in FIG. 5, and may be a gentle curved shape.

The cutting insert 17 is located on the first end 3A side, on the outer periphery side, and forward in the rotational direction O2 with respect to the cartridge 19. The cutting insert 17 may be brazed to the cartridge 19, for example, or may have an insert hole 25 and be fixed to the cartridge 19 using an insert fixing tool 27 such as a screw, as in an example shown in FIG.

The length of the first cutting portion 5A in the direction along the rotation axis O1 is, for example, 1 mm to 10 mm. The length of the first cutting portion 5A in the radial direction of the rotation axis O1 is, for example, 0.5 mm to 10 mm.

The first cutting portion 5A may have a forward surface 29. The forward surface 29 is a surface of the first cutting portion 5A that is located forward in the rotational direction O2. The forward surface 29 may be formed by a cutting insert 17 as shown in FIG. 5. There are no particular limitations on the shape of the forward surface 29, and it may be, for example, a flat or curved shape, or may have uneven portions.

The front surface 29 may have a first side 31, a second side 33, and a first corner 35. In the example shown in FIG. 5, the first side 31 is located on the side of the first end 3A. In the example shown in FIG. 5, the second side 33 is located on the outer periphery side away from the rotation axis O1, and the first corner 35 is a corner connected to the first side 31 and the second side 33. Note that the corner here is not limited to a point where two sides intersect, but may be a region where two sides intersect macroscopically, and may be a curved shape or a straight line shape inclined with respect to each of the two sides microscopically.

In the example shown in FIG. 5, the first cutting edge 21 may be located on the first side 31. As described above, since the first side 31 is located on the side of the first end 3A, the first cutting edge 21 located on the first side 31 can be located on the side of the first end 3A in the cutting portion 5. In addition, the second cutting edge 23 may be located on the second side 33. As described above, since the second side 33 is located on the side away from the rotation axis O1, the second cutting edge 23 located on the second side 33 can be located on the side away from the rotation axis O1 in the cutting portion 5.

The first cutting portion 5A may have a third cutting edge 36 located at the first corner 35. The third cutting edge 36 may be connected to the first cutting edge 21 and the second cutting edge 23. The third cutting edge 36 is not limited to a curved shape, and may have a straight-line portion or may be an arc shape.

The first cutting portion 5A has a back surface 37 that faces the seat surface 13. Since the seat surface 13 faces forward in the rotation direction O2 of the rotation axis O1, the back surface 37 can be said to face backward in the rotation direction O2 of the rotation axis O1. The back surface 37 may be located on the side of the first end 3A of the main body 3. The shape of the back surface 37 is not particularly limited, and may be flat or curved, and may have uneven portions.

The first cutting portion 5A has an inner surface 39 located near the rotation axis O1 relative to the seat surface 13. The inner surface 39 may face the constraint side surface 15. Since the constraint side surface 15 faces the outer periphery, it can be said that the inner surface 39 faces in the direction toward the rotation axis O1, i.e., toward the inner periphery.

As shown in FIG. 5, the first cutting portion 5A has a first outer surface 41 located on the opposite side to the inner surface 39. The first outer surface 41 may face the outer periphery side, or may have a second outer surface 43. The first cutting portion 5A may also have a second outer surface 43. The second outer surface 43 may be located closer to the second end than the first outer surface 41. The second outer surface 43 may be a flat surface. The second outer surface 43 is contactable with the first fixing device 7A. More specifically, the second outer surface 43 is contactable with the screw head 45 of the first fixing device 7A.

The first cutting portion 5A may have a through hole 47. The through hole 47 may open on the inner side surface 39 and the second outer side surface 43. The first fastener 7A may be inserted into the through hole 47. The through hole 47 may extend from the outer periphery side to the inner periphery side so that the first fastener 7A can be easily inserted from the outer periphery side. The shape of the through hole 47 is not limited to the shape shown in FIG. 7 and the like.

The first pocket 9A may have a screw hole 48. In other words, the restraining side surface 15 (main body portion 3) may have the screw hole 48. The screw hole 48 may open toward the outer periphery. As shown in FIG. 7, when the first cutting portion 5A has a through hole 47, the first fixing device 7A may be inserted into the screw hole 48 through the through hole 47, and the first cutting portion 5A may be fixed to the main body portion 3.

The first cutting part 5A may have a central axis N1. Here, the central axis N1 is not a tangible object of the first cutting part 5A. Furthermore, when the first cutting part 5A is fixed to the main body part 3, the first cutting part 5A may rotate around the central axis N1. There are no particular limitations on the shape of the first cutting part 5A, and in FIG. 9, the first cutting part 5A has a substantially cylindrical shape.

The back surface 37 may be in contact with the seat surface 13 as shown in FIG. 6, etc. In such a case, the seat surface 13 can receive the cutting load applied to the first cutting portion 5A through the back surface 37, so cutting can be performed stably. Note that the entire seat surface 13 and the back surface 37 do not need to be in contact; for example, as shown in FIG. 6, only a portion of the seat surface 13 and the back surface 37 may be in contact.

The back surface 37 has an outer region 49 and an inner region 51. Here, the outer region 49 refers to the region of the back surface 37 that is located on the outer periphery side and is in contact with the seat surface 13 as shown in FIG. 6. The inner region 51 refers to the region of the back surface 37 that is connected to the inner surface 39 and the outer region 49 and is separated from the seat surface 13.

When viewed from the first end 3A side, a virtual straight line L1 is set that passes through the end point of the cutting insert 17 closer to the rotation axis O1 and is perpendicular to the front surface 29. The entire outer region 49 may be located on the outer periphery side of the virtual straight line L1. In addition, the inner region 51 may intersect with the virtual straight line L1.

When fixing the first cutting part 5A to the main body part 3, first, as shown in FIG. 7, the first fixing tool 7A is inserted into the screw hole 48 through the through hole 47. That is, FIG. 7 shows the state in the middle of fixing the first cutting part 5A to the main body part 3 using the first fixing tool 7A. In FIG. 7, the first fixing tool 7A is not completely inserted into the screw hole 48, but rather a part of the first fixing tool 7A near the bottom 53 is shown inserted into the screw hole 48.

When the first fastener 7A inserted into the screw hole 48 is screwed, the screw head 45 of the first fastener 7A comes into contact with the second outer surface 43, and the load caused by screwing begins to be applied to the first cutting portion 5A, as shown in FIG. 7. At this time, the screw head 45 comes into contact with the second outer surface 43 behind the central axis N1 of the first cutting portion 5A in the rotation direction O2 of the rotation axis O1, and the screw head 45 is separated from the second outer surface 43 ahead of the central axis N1 of the first cutting portion 5A in the rotation direction O2 of the rotation axis O1.

Figure 8 shows the first cutting portion 5A fastened by the first fastener 7A inserted into the screw hole 48. As described above, the first cutting portion 5A is rotatable around the central axis N1. Therefore, when the first fastener 7A is fastened with the screw head 45 and the second outer surface 43 in contact as shown in Figure 7, the first cutting portion 5A rotates clockwise around the central axis N1 as shown in Figure 8.

By rotating the first cutting portion 5A clockwise around the central axis N1, the inner peripheral portion of the back surface 37 moves away from the seat surface 13, and the outer peripheral portion of the back surface 37 is pressed against the seat surface 13. As a result, as shown in FIG. 8, when the first cutting portion 5A is fastened by the first fastener 7A, the back surface 37 can have an outer region 49 that contacts the seat surface 13 and an inner region 51 that is separated from the seat surface 13. The outer region 49 and the seat surface 13 may be in surface contact or point contact.

The impulse of the cutting load received by the cutting edge 11 in the first cutting portion 5A and transmitted to the main body 3 becomes larger the further away from the rotation axis O1 the outer periphery becomes. In this case, in the example cutting tool 1 shown in FIG. 6, the outer region 49 on the back surface 37 is in contact with the seat surface 13, so that the large impulse of the cutting load generated by the cutting edge 11 can be stably received by the main body 3.

This is because the outer peripheral portion of the back surface 37 is pressed against the seat surface 13, and therefore the outer peripheral portion of the back surface 37 is unlikely to separate from the seat surface 13, even if the cutting load fluctuates. Because the outer peripheral portion of the back surface 37 is in stable contact with the seat surface 13, the main body 3 can stably receive the large impulse cutting load generated by the cutting edge 11.

In particular, in the example shown in FIG. 6, the cutting edge 11 is located on the outer periphery of the first cutting portion 5A, so that the cutting load can be stably transmitted to the main body portion 3 in the outer region 49, which is the portion of the back surface 37 that is located behind the cutting edge 11 in the rotational direction O2.

The above effect can be achieved even if there is no through hole 47. Specifically, when the first fastener 7A is a set screw, the first fastener 7A may be tightened to press the portion of the bottom 53 of the first fastener 7A located rearward in the rotation direction O2 of the rotation axis O1 against the second outer surface 43, thereby pressing the back surface 37 against the seat surface 13. In such a case, during cutting, the main body 3 can stably receive the cutting load applied to the first cutting portion 5A through the contact portion between the back surface 37 and the seat surface 13, thereby reducing the occurrence of chatter vibration.

If the entire back surface 37, i.e., both the inner region 51 and the outer region 49 of the back surface 37, are configured to be in contact with the seat surface 13, when the first cutting portion 5A is fastened to the main body portion 3 by the first fastener 7A, there is a risk that the inner region 51 will come into contact with the seat surface 13 while the outer region 49 will move away from the seat surface 13 due to manufacturing variations in the first cutting portion 5A and the main body portion 3. Also, even if both the inner region 51 and the outer region 49 are in contact with the seat surface 13 when the first cutting portion 5A is fastened to the main body portion 3 by the first fastener 7A, there is a risk that the inner region 51 will come into contact with the seat surface 13 while the outer region 49 will move away from the seat surface 13 due to fluctuations in the cutting load.

However, in the example shown in FIG. 8, the inner region 51 on the back surface 37 is separated from the seat surface 13, so that the outer region 49 on the back surface 37 is likely to come into stable contact with the seat surface 13. Also, because there is a certain gap between the inner region 51 and the seat surface 13, the first cutting portion 5A can be easily attached to the main body 3. Note that there may be a gap of 0.2 mm to 1 mm between the seat surface 13 and the inner region 51.

In addition, when the ridgeline located on the side of the first end 3A in the outer region 49 is defined as the outer ridgeline 55, and the ridgeline located on the side of the first end 3A in the inner region 51 is defined as the inner ridgeline 57, as shown in FIG. 6, the outer ridgeline 55 may be in contact with the seat surface 13, and the inner ridgeline 57 may be separated from the seat surface 13.

The first cutting portion 5A may have a cutting hole 59 facing the insert hole 25. The insert fixing device 27 may be inserted into the cutting hole 59 through the insert hole 25 to fix the cutting insert 17 to the cartridge 19. The cutting hole 59 is not limited to a so-called blind hole, and may penetrate to the back surface 37 as shown in FIG. 10. FIG. 10 is a view of the first cutting portion 5A in FIG. 9 as viewed from the A4 direction.

When the cutting tool 1 is seen through from the first end 3A side, the outer region 49 may be located behind the cutting insert 17 as shown in FIG. 8, or behind the first cutting edge 21. In such a case, the seat surface 13 can stably receive the cutting load applied to the first cutting portion 5A through the back surface 37.

Also, as shown in FIG. 8, the outer region 49 may contact the seat surface 13 behind the insert hole 25. In other words, the outer region 49 may contact the seat surface 13 behind the machined hole 59. Specifically, as shown in FIG. 8, when viewed in plan view from the first end 3A side, the seat surface 13 may contact an area (hereinafter referred to as the "inter-point area S1") located between two intersections of the seat surface 13 and two imaginary extension lines extending from both ends of the machined hole 59 on the back surface 37.

When viewed from the first end 3A side, the back surface 37 and the seat surface 13 may be in contact with each other in the area S1 between the two points. In other words, the outer area 49 may be located in the area S1 between the two points. In such a case, the seat surface 13 can more stably receive the cutting load applied to the first cutting portion 5A through the back surface 37.

There are no particular limitations on the shapes of the outer region 49 and the inner region 51. For example, the inner region 51 may be flat. However, even in such a case, the boundary between the outer region 49 and the inner region 51 may be a curved surface.

The pocket 9 may have a curved portion 61 that is a curved surface shape. In other words, the main body portion 3 may have a curved portion 61. When viewed from the first end 3A side, the curved portion 61 may have a curved shape or a concave shape. In addition, the curved portion 61 may be located closer to the rotation axis O1 than the seat surface 13 and may be adjacent to the seat surface 13, or may be located between the seat surface 13 and the restraining surface 15 as shown in FIG. 4.

The curved portion 61 may be separated from the first cutting portion 5A. If the pocket 9 has a curved portion 61, the pocket 9 of the main body 3 and the portion located at the corner of the first cutting portion 5A can reduce the risk of collision with each other due to vibration during cutting, resulting in damage.

When the cutting tool 1 is viewed from the side of the first end 3A, the seating surface 13 may have a linear shape. In such a case, the seating surface 13 can efficiently receive the cutting load applied to the first cutting portion 5A through the back surface 37. Here, the linear shape does not have to be a strictly linear shape, and it is sufficient if it is a straight line when observed with the naked eye. The same effect can be achieved even when the entire seating surface 13 is flat.

Before the first cutting portion 5A is fastened by the first fastener 7A, the screw head 45 may abut against the second outer surface 43 only at a portion located rearward of the central axis N2 of the first fastener 7A in the rotational direction O2, as shown in FIG. 7. In such a case, when the first fastener 7A is fastened to the first cutting portion 5A, the screw head 45 presses the first cutting portion 5A rearward in the rotational direction O2, causing the first cutting portion 5A to rotate so that the seat surface 13 is pressed against the back surface 37, and the first cutting portion 5A can be stably fixed to the main body portion 3.

Here, before the first cutting portion 5A is fastened by the first fixing tool 7A, as shown in FIG.
This refers to the time when the bottom 53 of the first fastener 7A is inserted into the screw hole 48 and the screw head 45 makes point contact with the second outer surface 43. If the time when point contact is unknown, the time when the second outer surface 43 and the screw head 45 are in contact with each other and resistance is felt from the first fastener 7A in the process of inserting the first fastener 7A into the first cutting portion 5A may be defined as the time before the first fastener 7A is fastened to the first cutting portion 5A. Note that the time before the first fastener 7A is fastened to the first cutting portion 5A may be rephrased as the state in which the first fastener 7A is not fastened to the first cutting portion 5A.

In a cross section perpendicular to the rotation axis O1 before the first fixing device 7A is fastened to the first cutting portion 5A, the imaginary line extending the flat second outer surface 43 is the first imaginary line L21, the imaginary line extending the flat seating surface 13 is the second imaginary line L22, the angle between the first imaginary line L21 and the second imaginary line L22 is θ1, and in a planar perspective from a direction along the rotation axis O1, the angle between the second imaginary line L22 and the central axis N2 of the first fixing device 7A is θ2, then 90° > θ1 + θ2 may be satisfied.

Specifically, as shown in Fig. 7, before the first cutting portion 5A is fastened by the first fastener 7A, the third imaginary line L23 passes through the intersection P1 between the second imaginary line L22 and the central axis N2 of the first fastener 7A and is perpendicular to the first imaginary line L21. For the sake of convenience, the angle between the second imaginary line L22 and the third imaginary line L23 is defined as α. As shown in Fig. 8, when the first cutting portion 5A is fastened by the first fastener 7A, the first cutting portion 5A rotates around the central axis N1, and the angle α approaches θ2.

When the angle α is greater than the angle θ2, when the first cutting portion 5A is fastened by the first fixing tool 7A, the outer region 49 can be stably pressed against the seating surface 13 while separating the inner region 51 from the seating surface 13. From the relationship between the angles θ1, θ2, and α shown in FIG. 7 and the fact that the sum of the interior angles of the triangle is 180°,
θ1+α+90°=180°
∴ α＝90°－θ1
When the angle α is greater than the angle θ2, it is expressed as α>θ2.
α=90°-θ1>θ2
∴ 90°＞θ1＋θ2
The relationship is derived.

The cross section perpendicular to the rotation axis O1 referred to above is a cross section including the center of any of the faces or regions (first outer surface 41, second outer surface 43, seat surface 13, inner region 51), and may be a cross section of each of the faces or regions. Also, as shown in FIG. 7, the first virtual line L21 and the second virtual line L22 may be virtual lines extending the second outer surface 43 and seat surface 13 in a planar perspective view from a direction along the rotation axis O1.

When the cutting tool 1 is viewed from the first end 3A side, the distance W1 between the outer region 49 and the through hole 47 is larger than the distance W2 between the inner region 51 and the through hole 47. Generally, during cutting, the outer region 49 is more susceptible to load than the inner region 51. In such a case, the outer region 49, which is thick and has a large distance from the outer region 49 to the through hole 47, can stably withstand the cutting load applied to the first cutting portion 5A, while the inner region 51 is less susceptible to the cutting load, reducing the risk of deformation of the through hole 47 due to the cutting load.

The above-mentioned interval may be a interval along a straight line perpendicular to the front surface 29, or in the case where the perpendicular cannot be uniquely determined because the front surface 29 is not flat, the interval may be a interval in a direction perpendicular to the first cutting edge 21 or the seat surface 13. Moreover, the above-mentioned interval is not limited to the interval when the cutting tool 1 is seen through from the first end 3A side. For example, it may be the interval in a cross section including the back surface 37 and the through hole 47 and perpendicular to the rotation axis O1.

The comparison of the above spacing may be limited to the maximum or minimum of each spacing. For example, the maximum spacing between the outer region 49 and the through hole 47 may be compared with the maximum spacing between the inner region 51 and the through hole 47, or the minimum spacing between the outer region 49 and the through hole 47 with the minimum spacing between the inner region 51 and the through hole 47. Note that the above spacing is evaluated as the spacing between each region and the line located rearward in the direction of rotation O2, of the two lines at both ends of the through hole 47 in FIG. 8.

Before the first cutting portion 5A is fastened by the first fastener 7A, when the cutting tool 1 is viewed from the first end 3A side, the central axis N3 of the through hole 47 may be inclined with respect to the central axis N4 of the screw hole 48. The central axis N4 of the screw hole 48 may be referred to as the central axis N2 of the first fastener 7A. The inclination referred to above may be an angle between the central axis N3 of the through hole 47 and the central axis N4 of the screw hole 48 that is greater than 0°.

The inclination direction is not particularly limited. For example, in FIG. 7, when viewed from the first end 3A side, the central axis N3 of the through hole 47 is inclined forward in the rotation direction O2 of the rotation axis O1 relative to the central axis N4 of the screw hole 48. When an unexpected cutting load is applied to the outer periphery of the first cutting portion 5A during cutting processing and the portion of the through hole 47 on the side of the second outer surface 43 moves slightly backward in the rotation direction O2 of the rotation axis O1, the above configuration reduces the risk of collision between the first fixing device 7A and the through hole 47.

When the cutting tool 1 is viewed from the first end 3A side, the distance W3 between the seat surface 13 and the through hole 47 may become smaller as it approaches the rotation axis O1. Since the cutting load on the first cutting portion 5A increases as it moves away from the rotation axis O1, when the cutting tool 1 has the above configuration, it is possible to ensure a thickness of the first cutting portion 5A that corresponds to the magnitude of the cutting load.

The above-mentioned interval may be a interval along a straight line perpendicular to the front surface 29, or may be a interval in a direction perpendicular to the first cutting edge 21 or the seating surface 13 if the perpendicular cannot be determined univocally because the front surface 29 is not flat, etc. Furthermore, the above-mentioned interval is not limited to the interval when the cutting tool 1 is seen through from the first end 3A side. For example, it may be the interval in a cross section that includes the seating surface 13 and the through hole 47 and is perpendicular to the rotation axis O1.

Note that increasing closer to the rotation axis O1 does not necessarily mean that the above-mentioned distance continues to increase in the strict sense; for example, there may be some points where the above-mentioned distance does not change. Also, in FIG. 8, the distance between the seat surface 13 and the line located rearward in the rotation direction O2, of the two lines at both ends of the through hole 47, is set to the distance W3 between the seat surface 13 and the through hole 47.

When the cutting tool 1 is viewed from the first end 3A side, the distance W4 between the seat surface 13 and the back surface 37 may increase as the cutting tool approaches the rotation axis O1. Since the cutting load on the first cutting portion 5A increases as the cutting tool moves away from the rotation axis O1, when the cutting tool 1 has the above configuration, the thickness of the first cutting portion 5A can be secured to correspond to the magnitude of the cutting load, and the risk of deformation of the through hole 47 due to the cutting load can be reduced.

The above-mentioned interval may be the interval along a straight line perpendicular to the front face 29, or may be the interval in a direction perpendicular to the first cutting edge 21 or the seating surface 13 if the front face 29 is not flat and the perpendicular cannot be determined univocally. Furthermore, the above-mentioned interval is not limited to the interval when the cutting tool 1 is seen through from the first end 3A side. For example, it may be the interval in a cross section that includes the seating surface 13 and the back surface 37 and is perpendicular to the rotation axis O1.

Note that increasing closer to the rotation axis O1 does not necessarily mean that the above spacing must continue to increase in the strict sense; for example, there may be some locations where the above spacing does not change.

The inner surface 39 and the constraining side surface 15 may be in contact with each other. In such a case, the first cutting portion 5A can be stably fixed to the main body portion 3. The inner surface 39 and the constraining side surface 15 may be curved as shown in FIG. 8, etc. In such a case, the first cutting portion 5A can be easily attached to the main body portion 3 while ensuring the above-mentioned stable fixation. The inner surface 39 and the constraining side surface 15 may also be flat. In such a case, the first cutting portion 5A can be stably fixed to the main body portion 3. The inner surface 39 and the constraining side surface 15 may be parallel.

As shown in FIG. 11, the first cutting portion 5A may have a first portion 63 located on the first end 3A side, and a second portion 65 located closer to the second end than the first portion 63. The outer diameter R1 of the first portion 63 may be larger than the outer diameter R2 of the second portion 65, as shown in FIGS. 12 and 13. In such a case, it becomes easier to hold the cutting edge 11 in a stable position. Here, the outer diameter may be compared to the radius from the central axis N1 when the first portion 63 or the second portion 65 is cylindrical.

In addition, when the first part 63 or the second part 65 is not cylindrical, the distances from the end points farthest from the central axis N5 of the first part 63 and the central axis N6 of the second part 65 may be compared, or the distances from the end points closest to the central axis N5 of the first part 63 and the central axis N6 of the second part 65 may be compared. In addition, when the outer diameter is not constant from the first end 3A side to the second end side in the first part 63 and the second part 65, the outer diameter at the midpoint of each part in the direction along the rotation axis O1 may be evaluated.

FIG. 11 is a view of the first cutting portion 5A in FIG. 9 as viewed from the A5 direction. FIG. 12 is an enlarged cross-sectional view of the cutting tool 1 cut along line XII-XII in FIG. 2. The XII-XII cross section passes through the first portion 63 and is perpendicular to the rotation axis O1. FIG. 13 is an enlarged cross-sectional view of the cutting tool 1 cut along line XIII-XIII in FIG. 2. The XIII-XIII cross section passes through the second portion 65 and is perpendicular to the rotation axis O1.

The first part 63 may have a back surface 37. The first part 63 may have a cutting edge 11. In FIG. 12, the first part 63 has a back surface 37 and a cutting insert 17. When the back surface 37 and the cutting edge 11 are in the same part, the cutting load can be stably received by the back surface 37. The second part 65 may also have a second outer surface 43 and an inner surface 39. In FIG. 13, the second part 65 has a second outer surface 43 and an inner surface 39. In the above case, that is, when the cutting edge 11 and the inner surface 39 are in different parts, an excessive cutting load is applied to the first fixture 7A, and the risk of deformation of the first fixture 7A can be reduced.

The second portion 65 may have a through hole 47 as shown in FIG. 5. In this way, when the cutting edge 11 and the through hole 47 are in different parts, the risk of deformation of the through hole 47 due to excessive cutting load on the through hole 47 can be reduced, and the thickness of the cutting portion 5 can be secured.

The cutting tool 1 may have an adjustment member 67 between the main body 3 and the first cutting part 5A. When the cutting tool 1 has the adjustment member 67, the cutting edge position of the cutting blade 11 can be adjusted by the adjustment member 67. The adjustment member 67 may have an adjustment hole 69.

The adjustment member 67 may have an adjustment hole 69. The cutting edge position of the cutting blade 11 can be adjusted by inserting a wrench or the like into the adjustment hole 69 and turning it. The opening of the adjustment hole 69 may face the outer periphery of the rotation direction O2 of the rotation axis O1. In such a case, a wrench or the like can be easily inserted into the adjustment hole 69. The adjustment member 67 may be covered by the main body 3 except for a portion where the adjustment hole 69 is located. In such a case, the risk of the adjustment member 67 flying off during cutting can be reduced.

When the cutting tool 1 is viewed from the first end 3A side, the back surface 37 may be located behind the intersection P2 between the virtual straight line L3 extending from the second outer surface 43 and the first outer surface 41 in the rotation direction O2 of the rotation axis O1. In such a case, the thickness of the outer periphery of the first cutting portion 5A can be secured, and cutting can be performed stably.

The screw head 45 may face the outer periphery of the rotation axis O1 as shown in FIG. 8. In such a case, the first fixing device 7A can be easily inserted into the first cutting portion 5A. Also, when the cutting tool 1 is seen through from the second end side, the screw head 45 and the first portion 63 may overlap. In such a case, the risk of the first fixing device 7A being damaged by chips hitting the first portion 63 during cutting processing can be reduced. For example, as shown in FIG. 10, the first cutting portion 5A may have a cutting pocket 71, and the upper portion of the cutting pocket 71 may have a curved shape that covers part of the cutting insert 17 from above.

When the cutting tool 1 is viewed from the first end 3A side, the angle between the seat surface 13 and the first cutting edge 21 may be an angle that opens outward. In such a case, the distance between the cutting edge 11 of the first cutting portion 5A and the seat surface 13 becomes large, and the thickness can be ensured, allowing for stable cutting. The first cutting edge 21 may be replaced with the front surface 29.

When the cutting tool 1 is viewed from the side of the first end 3A, the seating surface 13 and the first cutting edge 21 may be parallel. In such a case, the seating surface 13 can stably receive the cutting load related to the first cutting portion 5A through the back surface 37. Here, parallel does not strictly mean that the angle between the straight line extending from the seating surface 13 and the straight line extending from the first cutting edge 21 is 0°. If the angle is between -5° and 5°, the seating surface 13 and the first cutting edge 21 may be considered to be parallel. The first cutting edge 21 may be replaced with the front surface 29.

Materials for the cutting insert 17 include, for example, cemented carbide, cermet, and hard materials. Examples of cemented carbide compositions include WC-Co, WC-TiC-Co, and WC-TiC-TaC-Co. WC-Co is produced by adding cobalt (Co) powder to tungsten carbide (WC) and sintering the mixture. WC-TiC-Co is produced by adding titanium carbide (TiC) to WC-Co. WC-TiC-TaC-Co is produced by adding tantalum carbide (TaC) to WC-TiC-Co.

Cermets are sintered composite materials that combine ceramic components with metals. Specifically, cermets include those that are primarily composed of titanium compounds such as titanium carbide (TiC) and titanium nitride (TiN). Hard materials include, for example, cBN (Cubic Boron Nitride) and PCD (PolyCrystalline Diamond).

The surface of the cutting insert 17 may be coated with a coating by using a chemical vapor deposition (CVD) method or a physical vapor deposition (PVD) method. The coating composition may include titanium carbide (TiC), titanium nitride (TiN), titanium carbonitride (TiCN), alumina ( _Al2O3 ) _, and the like.

The main body 3 may be made of a material such as steel, cast iron, or aluminum alloy. From the viewpoint of increasing toughness, the main body 3 may be made of steel.

<Method of manufacturing machined products>
Next, a method for manufacturing the machined product 101 according to a non-limiting embodiment will be described in detail using the cutting tool 1 according to the non-limiting embodiment described above as an example. The description will be given below with reference to Figs. 14 to 16. Figs. 14 to 16 illustrate the steps of cutting the workpiece 102 as an example of the method for manufacturing the machined product 101. To facilitate visual understanding, the machined parts are hatched in Fig. 16.

The manufacturing method of the machined product 101 according to the non-limiting embodiment may include the following steps (1) to (3).

(1) The cutting tool 1 may be rotated in a rotation direction O2 around the rotation axis O1, and brought closer to the workpiece 102 in a feed direction Y1 (see FIG. 14).

This process can be carried out, for example, by fixing the workpiece 102 on the table of a machine tool to which the cutting tool 1 is attached, and bringing the cutting tool 1 closer while rotating. Note that in this process, it is sufficient that the workpiece 102 and the cutting tool 1 are relatively close to each other, and the workpiece 102 may be brought closer to the cutting tool 1.

(2) The cutting tool 1 may be brought even closer to the workpiece 102, so that the rotating cutting tool 1 comes into contact with the desired position on the surface of the workpiece 102, thereby cutting the workpiece 102 (see FIG. 15).

In this process, the cutting edge 11 may be brought into contact with a desired position on the surface of the workpiece 102.

(3) The cutting tool 1 may be moved away from the workpiece 102 in the Y2 direction (see Figure 16).

In this process, as in the above-mentioned process (1), the cutting tool 1 may be moved relatively away from the workpiece 102, for example, the workpiece 102 may be moved away from the cutting tool 1. In addition to the milling process shown in the figure, examples of cutting processes include plunge machining, copying, and oblique sinking.

By going through the above process, it is possible to achieve excellent workability.

When cutting the workpiece 102 as described above is performed multiple times, for example, when performing multiple cutting operations on one workpiece 102, the cutting tool 1 may be kept rotating while repeatedly contacting different locations on the workpiece 102.

Examples of the material of the workpiece 102 include carbon steel, alloy steel, stainless steel, cast iron, and non-ferrous metals.

1... Cutting tool 3... Main body 3A... Tip (first end)
3B... rear end (second end)
5: Cutting portion 5A: First cutting portion 7: Fixing device 7A: First fixing device 9: Pocket 9A: First pocket 11: Cutting edge 13: Seat surface 15: Restraint side surface 17: Cutting insert 19: Cartridge 21: First cutting edge 23: Second cutting edge 25: Insert hole 27: Insert fixing device 29: Front surface 31: First side 33: Second side 35: First corner 36: Third cutting edge 37: Back surface 39: Inner surface 41: First outer surface 43: Second outer surface 45: Screw head 47: Through hole 48: Screw hole 49: Outer region 51: Inner region 53: Bottom 55: Outer ridge 57: Inner ridge 59: Cutting hole 61: Curved portion 63: First portion 65: Second portion 67: Adjustment member 69: Adjustment hole 71: Cutting pocket 101: Cutting workpiece 102: Workpiece O1: Rotation axis O2: Rotation direction N1, N2, N3, N4, N5, N6: Central axis L1, L3: Virtual line L21: First virtual line L22: Second virtual line L23: Third virtual line S1: Area between two points W1, W2, W3, W4: Interval P1, P2: Intersection R1, R2: Outer diameter Y1: Feed direction

Claims (11)

A main body portion extending from a front end to a rear end along a rotation axis and having a pocket located on the front end side;
A cutting portion located in the pocket and having a cutting edge located on the side of the tip;
a fixing device that fixes the cutting portion to the main body portion,
The pocket is
A seat surface facing the rotation direction of the rotation shaft;
a restraining side surface located near the axis of rotation relative to the seating surface;
The cutting portion is
A back surface facing the seat surface;
An inner surface facing the restraining side surface;
a first outer surface opposite the inner surface;
a second outer surface that is located closer to the rear end than the first outer surface and that is in contact with the fixing device,
The back surface is
an outer region located on the outer periphery side and in contact with the seat surface;
an inner region connected to the inner surface and the outer region and spaced from the seating surface. The second outer surface and the seat surface are flat,
In a state where the cutting portion is not fastened by the fastener,
In a cross section perpendicular to the rotation axis, a virtual line extending the second outer surface is a first virtual line, a virtual line extending the seat surface is a second virtual line, and an angle formed by the first virtual line and the second virtual line is a first angle,
In a planar perspective view from a direction along the rotation axis, an angle between the second virtual line and a central axis of the fixing device is a second angle,
2. The cutting tool according to claim 1, wherein 90°>( angle of the first angle)+( angle of the second angle). The cutting portion further has a through hole that opens on the second outer surface and the inner surface and into which the fixing tool is inserted,
When the tip is visualized,
The cutting tool according to claim 1 , wherein a distance between the outer region and the through hole is greater than a distance between the inner region and the through hole. The pocket further has a screw hole that opens on the restraining side surface and faces the through hole,
In a state where the cutting portion is not fastened by the fastener,
The cutting tool according to claim 3 , wherein a central axis of the through hole is inclined with respect to a central axis of the screw hole. The fastener has a screw head that abuts the second outer surface,
In a state where the cutting portion is not fastened by the fastener,
The cutting tool according to claim 3 or 4, wherein the screw head abuts against the second outer surface only on the opposite side in the rotation direction from a central axis of the through hole. The cutting tool according to any one of claims 3 to 5, in which the distance between the seat and the through hole becomes smaller as it approaches the rotation axis when viewed from the tip. The cutting tool according to any one of claims 1 to 6, in which, when viewed from the tip, the distance between the seat surface and the back surface increases as the tool approaches the rotation axis. The cutting tool according to any one of claims 1 to 7, wherein the inner surface and the restraining surface abut each other and have a curved shape. The cutting portion is
A first portion located on the tip side;
a second portion located closer to the rear end than the first portion,
The outer diameter of the first portion is greater than the outer diameter of the second portion,
the back surface and the first outer surface are located on the first portion;
The cutting tool according to any one of claims 1 to 8, wherein the second outer surface is located on the second portion. The second outer surface is flat;
When the tip is visualized,
The cutting tool according to claim 9 , wherein the back surface is located on an opposite side in a rotation direction of the rotation shaft from an intersection point between the first outer surface and an imaginary straight line extending from the second outer surface. A step of rotating the cutting tool according to any one of claims 1 to 10;
contacting the cutting tool with a workpiece;
and removing the cutting tool from the workpiece.

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