CN114951768B - Rotary cutting tools - Google Patents
Rotary cutting tools Download PDFInfo
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- CN114951768B CN114951768B CN202210162557.XA CN202210162557A CN114951768B CN 114951768 B CN114951768 B CN 114951768B CN 202210162557 A CN202210162557 A CN 202210162557A CN 114951768 B CN114951768 B CN 114951768B
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- cutting edge
- tool head
- chamfer
- edge
- cutting
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- 230000002093 peripheral effect Effects 0.000 claims abstract description 62
- 230000009467 reduction Effects 0.000 claims abstract description 38
- 230000007423 decrease Effects 0.000 claims abstract description 29
- 239000000463 material Substances 0.000 claims description 29
- 238000009825 accumulation Methods 0.000 claims description 10
- 230000000052 comparative effect Effects 0.000 description 21
- 238000005553 drilling Methods 0.000 description 9
- 239000012530 fluid Substances 0.000 description 5
- 238000000034 method Methods 0.000 description 4
- 239000002173 cutting fluid Substances 0.000 description 3
- 238000010586 diagram Methods 0.000 description 3
- 239000011247 coating layer Substances 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000003754 machining Methods 0.000 description 2
- 230000008569 process Effects 0.000 description 2
- 238000012545 processing Methods 0.000 description 2
- 229910052582 BN Inorganic materials 0.000 description 1
- PZNSFCLAULLKQX-UHFFFAOYSA-N Boron nitride Chemical compound N#B PZNSFCLAULLKQX-UHFFFAOYSA-N 0.000 description 1
- 229910000997 High-speed steel Inorganic materials 0.000 description 1
- 230000004075 alteration Effects 0.000 description 1
- -1 cemented carbide Substances 0.000 description 1
- 239000000919 ceramic Substances 0.000 description 1
- 239000011195 cermet Substances 0.000 description 1
- 229910003460 diamond Inorganic materials 0.000 description 1
- 239000010432 diamond Substances 0.000 description 1
- 238000007599 discharging Methods 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 238000003801 milling Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012887 quadratic function Methods 0.000 description 1
- 238000007790 scraping Methods 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23B—TURNING; BORING
- B23B51/00—Tools for drilling machines
- B23B51/08—Drills combined with tool parts or tools for performing additional working
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23B—TURNING; BORING
- B23B51/00—Tools for drilling machines
- B23B51/02—Twist drills
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23B—TURNING; BORING
- B23B2251/00—Details of tools for drilling machines
- B23B2251/12—Cross sectional views of the cutting edges
- B23B2251/122—Bevelled cutting edges
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23B—TURNING; BORING
- B23B2251/00—Details of tools for drilling machines
- B23B2251/18—Configuration of the drill point
- B23B2251/182—Web thinning
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23C—MILLING
- B23C2210/00—Details of milling cutters
- B23C2210/12—Cross section of the cutting edge
- B23C2210/123—Bevelled cutting edges
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23C—MILLING
- B23C5/00—Milling-cutters
- B23C5/02—Milling-cutters characterised by the shape of the cutter
- B23C5/10—Shank-type cutters, i.e. with an integral shaft
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23D—PLANING; SLOTTING; SHEARING; BROACHING; SAWING; FILING; SCRAPING; LIKE OPERATIONS FOR WORKING METAL BY REMOVING MATERIAL, NOT OTHERWISE PROVIDED FOR
- B23D77/00—Reaming tools
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Drilling Tools (AREA)
Abstract
一种具有包括切削刃的工具头部的旋转切削工具。该切削刃包括倒角部段。倒角部段的倒角宽度在从第一位置到第二位置的第一区域中是恒定的，第一位置在倒角部段的靠近工具头部的中心的部分处，第二位置在倒角部段的比第一位置更靠近工具头部的外周边缘的部分处。在从第二位置到第三位置的第二区域中，倒角宽度从第二位置朝向第三位置逐渐地减小，第三位置在倒角部段的比第二位置更靠近工具头部的外周边缘的部分处，并且第二位置被设定为倒角宽度的减小开始位置。
A rotary cutting tool having a tool head including a cutting edge. The cutting edge includes a chamfer section. The chamfer width of the chamfer section is constant in a first region from a first position to a second position, the first position being at a portion of the chamfer section close to the center of the tool head, the second position being at a portion of the chamfer section closer to the peripheral edge of the tool head than the first position. In a second region from the second position to a third position, the chamfer width gradually decreases from the second position toward the third position, the third position being at a portion of the chamfer section closer to the peripheral edge of the tool head than the second position, and the second position being set as a start position for the reduction of the chamfer width.
Description
Technical Field
The present disclosure relates to rotary cutting tools.
Background
JP S60-175513U (unexamined patent application or publication of registered utility model) discloses a drill bit as a rotary cutting tool. In the drill, the cutting edge of the tool head is chamfered to prevent damage to the cutting edge. Thus, the cutting edge comprises a chamfer section.
In this drill bit, the chamfer width of the chamfer section is the length of the chamfer section in the axial direction of the drill bit. The chamfer widths include a first chamfer width and a second chamfer width. The first chamfer width is constant in a direction from the center toward the outer peripheral edge of the tool head of the drill (radial direction of the drill) throughout the first region. On the other hand, in the entire second region, the second chamfer width is smaller than the first chamfer width in the first region in the direction from the first region toward the outer peripheral edge of the tool head, and the second chamfer width is constant.
Disclosure of Invention
The first drill bit, wherein the cutting edge comprises a chamfer section, has a lower sharpness than the second drill bit, wherein the cutting edge does not comprise a chamfer section. The low sharpness of the first drill leads to high cutting resistance, resulting in various problems such as low machining accuracy. Thus, the first drill comprising a cutting edge with a chamfer section preferably has a higher sharpness. This is not limited to a drill bit, but is equally applicable to rotary cutting tools that include cutting edges with chamfer sections in addition to drill bits.
In view of the above, one or more aspects of the present disclosure are directed to providing a rotary cutting tool including a cutting edge having a chamfer section and having a high sharpness.
In order to achieve the above object, a rotary cutting tool as an aspect of the present disclosure is a rotary cutting tool for cutting a workpiece. The rotary cutting tool comprises a cutting edge 4, cutting edge forming surfaces 11, 14 and a clearance surface 12. The cutting edge 4 is provided in a predetermined region from the outer peripheral edge of the tool head 3 of the rotary cutting tool to the center of the tool head in the radial direction D3 of the rotary cutting tool. Cutting edge forming surfaces 11, 14 are provided in the tool head 3 and are provided for forming cutting edges. The clearance surface 12 is provided in the tool head, forms a cutting edge in a portion of the tool head between the cutting edge forming surface and the clearance surface, and forms a clearance between the tool head and the workpiece. The cutting edge is provided in a portion of the tool head between the cutting edge forming face and the clearance face, and the cutting edge comprises a chamfer section 13, 15, at least a portion of the chamfer section 13, 15 being a planar face. The chamfer width W1 of the chamfer section is the length of the chamfer section in the axial direction D1 of the rotary cutting tool. The value of the chamfer width W1 is constant in a first region from a first position P1 at a portion of the chamfer section near the center of the tool head to a second position P2 at a portion of the chamfer section closer to the outer peripheral edge of the tool head than the first position. In a second region from the second position to a third position P3, the value of the chamfer width decreases from the second position toward the third position, the third position P3 being located at a portion of the chamfer section closer to the outer peripheral edge of the tool head than the second position. The second position is set as a reduction start position of the chamfer width at which the chamfer width starts to be reduced.
The inventors have found that a drill bit having the above configuration, including a cutting edge having a chamfer section, has a high sharpness. Due to the cutting edge including the chamfer section having the above-described configuration, during cutting processing of the workpiece, a portion of the workpiece cut from the workpiece is continuously attached to the chamfer section as an accumulated material accumulated in the chamfer section. This makes the accumulated material attached to the chamfer section of the cutting edge a sharp, stacked edge. Thus, a drill bit comprising a cutting edge with a chamfer section may have a high sharpness.
Reference numerals in brackets assigned to the respective components denote examples of correspondence between the components and specific components in the embodiments described later.
Drawings
In the drawings:
FIG. 1 is a schematic diagram illustrating a tool head of a drill bit of a first embodiment;
FIG. 2A is an overall view of the drill bit of FIG. 1;
FIG. 2B is a perspective view of the drill bit of FIG. 1;
FIG. 3 is a side view of the drill bit of FIG. 1;
FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. 3;
Fig. 5 is a graph showing a comparison result of sharpness between the drill of example 1 and the drill of comparative example 1;
FIG. 6 is a schematic diagram illustrating a tool head of a drill bit of a second embodiment;
FIG. 7 is a perspective view of the drill bit of FIG. 6;
FIG. 8 is a schematic diagram illustrating a tool head of a drill bit of a third embodiment; and
Fig. 9 is a perspective view of the drill bit of fig. 8.
Detailed Description
Embodiments of the rotary cutting tool of the present disclosure will be described below with reference to the accompanying drawings. In the following description of the embodiments, components identical or equivalent to each other are denoted by the same reference numerals.
(First embodiment)
The drill 1 of the present embodiment shown in fig. 1 to 3 is a cutting tool for drilling, for example, and the drill 1 is a rotary cutting tool for cutting a workpiece when at least one of the drill 1 and the workpiece is rotated. During rotation of the drill bit 1, the drill bit 1 rotates about the axis L1. The axis L1 is also the center line of the drill bit 1. The drill bit 1 comprises a bit body 2 and a shank portion S, as shown in fig. 2A.
The bit body 2 shown in fig. 2A, 2B, and 3 is a portion of the drill bit 1 located on the tip end side of the drill bit 1 in the axial direction D1. The axial direction D1 is a direction parallel to the axis L1. The bit body 2 has a tool head 3, the tool head 3 comprising a cutting edge 4 for cutting a workpiece. The cutting edge 4 extends in the radial direction D3 of the drill bit 1 from a position near the outer peripheral edge of the tool head 3 toward the center of the tool head 3. The cutting edge 4 is provided in a predetermined region from the outer peripheral edge of the tool head 3 to the center C1 of the tool head 3 in the radial direction D3 of the drill bit 1. The position of the center C1 of the tool head 3 coincides with the position through which the axis L1 passes in the tool head 3. The bit body 2 has a groove 5, and the groove 5 is used for discharging chips (a portion of the workpiece cut from the workpiece) generated when the workpiece is cut by the cutting edge 4. The recess 5 extends in the axial direction D1 from the tool head 3 of the drill bit 1 towards the rear end of the drill bit 1. The groove 5 is provided in a predetermined area from the tool head 3 of the drill bit 1 to the rear end of the drill bit 1 in the axial direction D1. Furthermore, the grooves 5 are arranged in a spiral shape around the axis L1. The shank portion S is a portion of the drill bit 1 closer to the rear end of the drill bit 1 than the bit body 2. The shank portion S is held by the rotational axis of the working tool.
The drill bit 1 includes a material such as high-speed steel, cemented carbide, cermet, ceramics, CBN (cubic boron nitride) sintered body or diamond sintered body, and a coating layer covering the material. The drill bit 1 may not necessarily comprise a coating layer. The entire drill bit 1 may not necessarily be made of the above-mentioned materials. The drill bit 1 may be configured such that only the tool head 3 of the drill bit 1 is made of the above-mentioned materials.
As shown in fig. 1 and 2B, the bit body 2 has two groups of portions, each of the two groups including a rake surface 11, a clearance surface 12, a main cutting edge 13, a thinning portion 14, and a thinning cutting edge 15. The bit body 2 comprises first portions, each of which comprises a rake surface 11, a clearance surface 12, a main cutting edge 13, a thinning 14 and a thinning cutting edge 15. The bit body 2 has at least two first portions. That is, the bit body 2 has a second portion including at least two sets of first portions. The first part will be described below. A rake surface 11, a clearance surface 12, a main cutting edge 13, a thinned portion 14 and a thinned cutting edge 15 are provided in the tool head 3. The main cutting edge 13 and the reduced cutting edge 15 constitute the cutting edge 4. In fig. 1 and 2B, the cutting edge 4 is hatched for clarity. The same applies to fig. 6 to 9.
The rake face 11 is positioned closer to the outer peripheral edge of the tool head 3 than the center C1 of the tool head 3 in the radial direction D3 of the drill bit 1. The rake surface 11 is a surface disposed adjacent to the surface of the main cutting edge 13. The rake face 11 is a face for scraping off a portion of the workpiece that is cut and removed from the workpiece. In the tool head 3, the rake face 11 is located on the front side of the inner wall surface constituting the recess 5 in the rotation direction D2 of the drill 1. The main cutting edge 13 is formed in a portion of the tool head 3 between the clearance surface 12 and the rake surface 11. Thus, the rake surface 11 is a first cutting edge forming surface for forming the cutting edge 4.
When the tool head 3 is cut into the workpiece, the clearance surface 12 forms a clearance between the tool head 3 and the workpiece to avoid unnecessary friction between the tool head 3 and the workpiece. The gap is a space. The clearance surface 12 is located rearward of the rake surface 11 in the rotational direction D2 of the drill bit 1. Thus, the clearance surface 12 is a second cutting edge forming surface for forming a space between the tool head 3 and the workpiece. The cutting edge 4 is formed in a portion of the tool head 3 between the rake surface (first cutting edge forming surface) 11 and the clearance surface 12.
The clearance surface 12 includes a first clearance surface 121 and a second clearance surface 122. The main cutting edge 13 is formed in a portion of the tool head 3 between the rake surface 11 and the first clearance surface 121. The second clearance surface 122 is provided immediately behind the first clearance surface 121 in the rotation direction D2 of the drill bit 1. The second clearance surface 122 is a surface located rearward of the first clearance surface 121 in the rotation direction D2 of the drill bit 1 and disposed adjacent to the first clearance surface 121. The first clearance surface 121 and the second clearance surface 122 are not parallel to each other but intersect each other. The clearance face 12 has a fluid aperture 123. During drilling, cutting fluid is ejected from the tool head 3 through the fluid holes 123. The clearance surface 12 may not necessarily have the fluid hole 123, as long as the cutting fluid can be supplied without the fluid hole 123.
The main cutting edge 13 is provided in a portion of the tool head 3 between the rake surface 11 and the clearance surface 12. In other words, the main cutting edge 13 is provided in a predetermined region from the end portion of the rake surface 11 to the end portion of the clearance surface 12. The main cutting edge 13 extends in the radial direction D3 of the drill bit 1 from a position near the outer peripheral edge of the tool head 3 toward the center of the tool head 3. The main cutting edge 13 is provided in a predetermined region from the outer peripheral edge of the tool head 3 to the center of the tool head 3 in the radial direction D3 of the drill bit 1.
The thinned portion 14 is provided in the tool head 3 immediately behind the clearance surface 12 in the rotational direction D2 of the drill bit 1. The thinned portion 14 has a face located behind the clearance face 12 in the rotational direction D2 of the drill bit 1 in the tool head 3 and disposed adjacent to the clearance face 12. The thinned portion 14 is provided in the tool head 3 immediately in front of the inner wall surface constituting the recess 5 in the rotation direction D2 of the drill bit 1. The thinned portion 14 has a face that is located in front of the inner wall face constituting the recess 5 in the tool head 3 in the rotation direction D2 of the drill bit 1 and is disposed adjacent to the inner wall face constituting the recess 5. In the thinned portion 14, a portion near the center of the tool head 3 is thinner than the rake face 11. The thinned portion 14 is provided to allow a portion of the tool head 3 near the center of the tool head 3 to have a smaller thickness than the rake face 11. The thinned cutting edge 15 is formed in a portion of the tool head 3 between the first clearance surface 121 and the thinned portion 14 at a position near the center of the tool head 3. Thus, the thinned portion 14 is a first cutting edge forming surface for forming the cutting edge 4.
More specifically, the thinned portion 14 includes a first thinned surface 141 and a second thinned surface 142. The thinned cutting edge 15 is formed in a portion of the tool head 3 between the first clearance surface 121 and the first thinned surface 141 at a position near the center of the tool head 3. The second thinning surface 142 is provided adjacent to the second clearance surface 122 of the clearance surface 12 of a different group than the group of clearance surfaces 12 including the first clearance surface 121. As shown in fig. 2B, the first thinning surface 141 is disposed immediately adjacent to the second thinning surface 142 so as to form an obtuse angle with the second thinning surface 142. The first thinning surface 141 is disposed adjacent to the second thinning surface 142 to form an obtuse angle with the second thinning surface 142. The intersection line 143 of the first thinning surface 141 and the second thinning surface 142 extends in the radial direction D3 of the drill 1 from a position near the outer peripheral edge of the tool head 3 toward the center C1 of the tool head 3. The intersecting line 143 further extends closer to the tip of the drill bit 1 in the axial direction D1.
The present embodiment shows an example in which the thinned portion 14 is of an X-type, but the type of the thinned portion 14 is not limited thereto. The thinned portion 14 may be of a type other than X-type. The thinned portion 14 is provided in order to reduce cutting resistance of the drill bit 1 and improve biting performance of the drill bit 1. Examples of types other than X-type of the thinned portion 14 include XR type, S type, and N type.
The thinning cutting edge 15 is provided between the thinning portion 14 and the clearance surface 12 at a position near the center of the tool head 3. The thinning cutting edge 15 is disposed immediately adjacent to the main cutting edge 13 at a position closer to the center of the tool head 3 than the main cutting edge 13. The thinning cutting edge 15 is located closer to the center of the tool head 3 than the main cutting edge 13 and is disposed adjacent to the main cutting edge 13. The cutting edge 4, comprising a main cutting edge 13 and a reduced cutting edge 15, extends in the radial direction D3 of the drill 1 from the peripheral edge of the tool head 3 to the center C1 of the tool head 3.
In the configuration of the present embodiment, the thinned cutting edge 15 and the main cutting edge 13 as cutting edges are chamfered. That is, each of the thinning cutting edge 15 and the main cutting edge 13 includes a chamfer section. At least a portion of the chamfer section is a planar face. The present embodiment shows an example in which the entire chamfer section is a flat face, but the chamfer section is not limited thereto. For example, the chamfer section may be configured such that the portion of the chamfer section other than the end portion of the chamfer section is a flat face and the end portion of the chamfer section is a curved face.
Fig. 4 is a cross-sectional view taken along line IV-IV in fig. 3. As shown in fig. 4, the chamfer angle θ1 is an angle formed by the axial direction D1 and a flat surface of a chamfer section constituting the cutting edge 4. The chamfer angle θ1 is constant in the radial direction D3 of the drill bit 1 throughout the chamfer section from an end of the chamfer section near the center of the tool head 3 to an end of the chamfer section near the peripheral edge of the tool head 3 (i.e., to the peripheral edge of the tool head 3). The chamfer angle θ1 is in a range of 10 ° or more and 50 ° or less. The present embodiment shows an example in which the chamfer angle θ1 is constant throughout the chamfer section, but the chamfer angle θ1 is not limited thereto. The chamfer angle θ1 may not necessarily be constant throughout the chamfer section.
As shown in fig. 4, the chamfer width W1 is the length of the chamfer section in the axial direction D1. As shown in fig. 1 to 3, the value of the chamfer width W1 is constant in the entire central region in the portion of the chamfer section near the center of the tool head 3. The central region is a first region from a first position P1 to a second position P2 in the radial direction D3 of the drill bit 1, the first position P1 being located at an end of the chamfer section closer to the center of the tool head 3, the second position P2 being located at a portion of the chamfer section closer to the outer peripheral edge of the tool head 3 than the first position P1. That is, the chamfer width W1 P1 of the chamfer section at the first position P1 and the chamfer width W1 P2 of the chamfer section at the second position P2 are the same value. The second position P2 is set as a reduction start position of the chamfer width W1, at which the chamfer width W1 starts to be reduced, and the chamfer width W1 gradually decreases from the reduction start position toward the outer peripheral edge of the tool head 3.
In the present embodiment, the first position P1 in the chamfer section is a position of an end of the thinned cutting edge 15 closer to the center of the tool head 3, and is a position of the center C1 of the tool head 3. The second position P2 in the chamfer section is an intermediate position in the main cutting edge 13. The intermediate position in the main cutting edge 13 is a predetermined position along the radial direction D3 of the drill bit 1 between a fourth position P4 and a third position P3, the fourth position P4 being located at an end of the main cutting edge 13 near the center of the tool head 3, the third position P3 being located at an end of the main cutting edge 13 near the peripheral edge of the tool head 3 (i.e., at the peripheral edge of the tool head 3). The chamfer width W1 gradually decreases in a second region from a middle position (second position P2) in the main cutting edge 13 to a third position P3 located at the outer peripheral edge of the tool head 3. That is, the value of the chamfer width W1 gradually decreases from the second position P2 toward the third position P3 in the main cutting edge 13. The value of the chamfer width W1 P3 at the third position P3 is smaller than the value of the chamfer width W1 P2 at the second position P2. The value of the chamfer width W1 decreases at a constant rate. The value of the chamfer width W1 may not necessarily decrease at a constant rate. For example, the chamfer width W1 may decrease according to a quadratic function.
The value of the chamfer width W1 is set based on the cutting length. The cutting length is a machining length in which a workpiece is machined in a feeding direction of the cutting edge 4 (a direction in which a tool is fed) per one rotation of the drill 1. The cutting length is calculated based on the feed rate f [ mm/rev ] of the drill bit 1. The feed rate f is the distance the drill bit 1 is fed in the axial direction D1 per rotation of the drill bit 1.
Specifically, the value (size) of the chamfer width W1 in the central region of the chamfer section is obtained by multiplying the cutting length by a first constant. In this embodiment, the value of the first constant is in the range of 1.0 or more and 3.0 or less. The value (size) of the chamfer width W1 at the third position P3 located at the outer peripheral edge of the tool head 3 in the chamfer section is obtained by multiplying the cutting length by a second constant. In this embodiment, the value of the second constant is smaller than the value of the first constant, and the value of the second constant is in the range of 0.3 or more and 1.0 or less.
The drill 1 of the present embodiment is used for drilling a workpiece. During drilling, when the drill bit 1 rotates about the axis L1, the drill bit 1 is fed into the workpiece with a tip side in the axial direction D1. Thus, the workpiece is cut by the thinning cutting edge 15 and the main cutting edge 13. Chips cut from the workpiece by the thinning cutting edge 15 and the main cutting edge 13 are discharged through the groove 5 in the axial direction D1 toward the rear end of the drill 1. The rotational speed N min -1 of the drill bit 1 during drilling is set in accordance with the material of the workpiece.
Next, the reason for setting the chamfer width W1 as described above will be explained.
During drilling, when the portion of the workpiece (chip) cut from the workpiece by the drill 1 adheres to the chamfer section as an accumulated material, the accumulated material functions as a cutting edge. The accumulated material used as the cutting edge is called a pile-up edge. During rotation of the drill bit 1, the cutting speed V m/min varies according to the position in the tool head 3 in the radial direction D3. Specifically, the cutting speed V is 0 at the center C1 of the tool head 3, and the cutting speed V increases in the radial direction D3 from the center C1 of the tool head 3 toward the outer peripheral edge of the tool head 3. That is, the cutting speed V at a position near the periphery of the tool head 3 is higher than the cutting speed V at a position near the center of the tool head 3. In the present embodiment, the cutting speed V is a relative speed of the drill and the workpiece in the circumferential direction at a predetermined position in the tool head 3 in the radial direction D3.
The inventors have found the following technical advantages of the stacked edge. When the cutting speed V exceeds the predetermined first speed, the pile edge becomes small and sharp. Therefore, a position at which the cutting speed V in the tool head 3 is a predetermined first speed is set as a reduction start position (second position P2 in the chamfer section) of the chamfer width W1. That is, the reduction start position of the chamfer width W1 may be defined according to the cutting speed V. This allows the sharp stacking edge to be continuously attached to the chamfer section. This configuration enables the drill bit 1 to have a high sharpness.
In the drill 1 of the present embodiment, when a workpiece made of a specific material is subjected to drilling at a predetermined rotational speed N, the cutting speed V at which sharp accumulation edges are formed in the chamfer section is 50m/min. The cutting speed V corresponds to the predetermined first speed described above. In the tool head 3, the cutting speed V at the intermediate position of the main cutting edge 13, i.e. at the second position P2 in the chamfer section, is 50m/min. Therefore, the intermediate position (second position P2 in the chamfer section) in the main cutting edge 13 is set as the reduction start position of the chamfer width W1.
Fig. 5 shows the result of the comparison of sharpness between the drill of example 1 and the drill of comparative example 1. Fig. 5 shows measurement results of the number of holes formed when drilling a workpiece repeatedly using each of the drill of example 1 and the drill of comparative example 1. The drill of example 1 is an example of the drill 1 of the present embodiment. That is, the drill of example 1 is configured such that the chamfer width of the main cutting edge decreases toward the outer peripheral edge of the tool head. In the drill of comparative example 1, the chamfer width of the entire thinning cutting edge and the entire main cutting edge is the same as and constant as that of the thinning cutting edge of example 1. That is, the drill of comparative example 1 is not configured such that the chamfer width of the main cutting edge decreases toward the outer peripheral edge of the tool head. Except for this, the drill of comparative example 1 has the same configuration as the drill 1 of the present embodiment.
The diameter of both the drill of example 1 and the drill of comparative example 1 was 4mm. The cutting speed at the peripheral edge of the tool head was 80m/min. The feed rate f was 0.17mm/rev. Drilling is performed as cutting fluid flows through a fluid hole provided in the drill bit. The chamfer angle θ of the drill bit is 25 °.
In the drill of example 1, the value of the chamfer width W1 P2 at the second position P2 as the reduction start position is obtained by multiplying the cutting length by 1.6. In the drill of example 1, the value of the chamfer width W1 P3 at the third position P3 located at the outer peripheral edge of the tool head 3 was obtained by multiplying the cutting length by 0.6. In the drill of comparative example 1, the value of the chamfer width W1 was obtained by multiplying the cutting length by 1.6.
As shown in fig. 5, in the drill of comparative example 1, when the number of holes exceeds 1000, the cutting edge is damaged, thereby preventing the drill from continuing to process. On the other hand, in the drill of example 1, even when the number of holes exceeds 3000, the cutting edge was not damaged, allowing the drill to continue to process. From the results shown in fig. 5, it was confirmed that the drill of example 1 had higher sharpness than the drill of comparative example 1.
In the drill of comparative example 1, the entire cutting edge had a uniform chamfer width, and the value of the chamfer width was the same as the maximum value of the chamfer width W1 in the drill of example 1. In the drill of comparative example 1, the chamfer width of the portion of the cutting edge near the outer peripheral edge of the tool head was larger than that of the drill of example 1. Therefore, in the drill of comparative example 1, the cutting edge has low sharpness and high cutting resistance. In the drill of comparative example 1, the portion of the cutting edge near the outer peripheral edge of the tool head has a large chamfer width; thus, it is assumed that the chamfer section has a region in which no accumulated material adheres.
On the other hand, in the drill of example 1, in the portion of the cutting edge near the outer peripheral edge of the tool head, the chamfer width gradually decreases toward the outer peripheral edge of the tool head. Specifically, in the drill of example 1, the reduction start position of the chamfer width of the main cutting edge is set as the following position in the main cutting edge: at this location, the cutting speed is the speed at which a sharp, stacked edge is formed in the chamfer section. The drill of example 1 is configured such that the chamfer width of the main cutting edge decreases from the decrease start position toward the outer peripheral edge of the tool head. Therefore, in the drill of example 1, the cutting edge is less likely to have low sharpness than the cutting edge in the drill of comparative example 1. In the drill of example 1, an amount of accumulated material, which is the portion of the workpiece cut from the workpiece, is attached to the chamfer section to form a sharp accumulation edge. Thus, as shown in fig. 5, the drill of example 1 has high sharpness.
JP 2004-268230A (published unexamined patent application) discloses a drill bit (hereinafter referred to as "drill a") comprising a cutting edge with a chamfer section. In bit a, the chamfer width is constant throughout the thinned cutting edge. In the drill a, the chamfer width gradually increases from a position of the boundary between the thinned cutting edge and the main cutting edge toward the outer peripheral edge of the tool head. That is, in the drill a, the position of the boundary between the thinned cutting edge and the main cutting edge corresponds to the position where the chamfer width starts to increase. Therefore, the chamfer width of the main cutting edge increases toward the outer peripheral edge of the tool head and is greater than the chamfer width of the thinned cutting edge.
Assuming that the value of the chamfer width of the thinning cutting edge of the drill a is the same as the value of the chamfer width W1 of the thinning cutting edge 15 of the present embodiment, the chamfer width of the main cutting edge of the drill a is larger than the chamfer width W1 of the main cutting edge 13 of the present embodiment. In the drill a having such a configuration, the main cutting edge has lower sharpness and higher cutting resistance than the main cutting edge in the drill 1 of the present embodiment. As in the drill of comparative example 1, in the drill a, it is estimated that the chamfer section has a region in which no accumulated material adheres. Therefore, the drill bit a has a lower sharpness than the drill bit 1 of the present embodiment.
The present inventors prepared the following drill as a drill (not shown) of comparative example 2: in this drill, the entire cutting edge has a uniform chamfer width, and the value of the chamfer width is the same as the minimum value of the chamfer width W1 in the drill of example 1. Except for this, the drill of comparative example 2 has the same configuration as the drill 1 of the present embodiment. Experiments conducted by the present inventors confirm that the drill bit of comparative example 2 has a lower sharpness than the drill bit 1 of the present embodiment. In the drill of comparative example 2, the area of the chamfer section is smaller than that in the drill 1 of the present embodiment. Therefore, in the drill of comparative example 2, it is estimated that the amount of accumulated material adhering to the chamfer section is small.
In the drill described in JP S60-175513U (hereinafter referred to as "drill B"), the chamfer width is constant throughout the thinned cutting edge. In the drill B, the chamfer width of the main cutting edge is smaller than that of the thinned cutting edge and is constant.
It is assumed that the value of the chamfer width of the thinning cutting edge of the drill B is the same as the value of the chamfer width W1 of the thinning cutting edge 15 of the present embodiment. The value of the chamfer width of the main cutting edge of the drill B is assumed to be the same as the minimum value of the chamfer width W1 of the main cutting edge 13 of the present embodiment. In the drill B having such a configuration, the area of the chamfer section of the main cutting edge is smaller than that of the main cutting edge in the drill 1 of the present embodiment. Therefore, in the drill B, it is estimated that the amount of accumulated material adhering to the chamfer section of the main cutting edge is small. Therefore, it is estimated that the drill B has a lower sharpness than the drill 1 of the present embodiment.
As described above, in the drill 1 of the present embodiment, the cutting edge 4 includes the thinning cutting edge 15 and the main cutting edge 13. Each of the thinning cutting edge 15 and the main cutting edge 13 comprises a chamfer section. The value of the chamfer width W1 is constant in the entire central region in the portion of the chamfer section near the center of the tool head 3. In the drill 1 of the present embodiment, in a portion of the chamfer section closer to the outer peripheral edge of the tool head 3 than the central region, the second position P2 at which the cutting speed is a speed at which a sharp accumulation edge is formed in the chamfer section is set as the reduction start position of the chamfer width W1. That is, in the drill 1 of the present embodiment, the reduction start position of the chamfer width W1 is set to the second position P2, at which the cutting speed is a speed at which the stacking edge becomes sharp and the sharp stacking edge continuously adheres to the chamfer section. The reduction start position of the chamfer width W1 is defined according to the following cutting speed: at this cutting speed, the stacking edge becomes sharp, and the sharp stacking edge continuously adheres to the chamfer section. In the drill 1 of the present embodiment, the chamfer width W1 of the main cutting edge 13 gradually decreases from the reduction start position toward the outer peripheral edge of the tool head 3. In the drill 1 of the present embodiment, since the chamfer section has such a configuration, during cutting processing of the workpiece, a portion of the workpiece cut from the workpiece (chip) is continuously attached to the chamfer section as an accumulated material accumulated in the chamfer section. This allows the accumulated material attached to the chamfer section to become a sharp accumulation edge. Thus, in the present embodiment, the drill including the cutting edge 4 having the chamfer section may have high sharpness.
(Second embodiment)
As shown in fig. 6 and 7, in the drill 100 of the present embodiment, the second position P2, which is a reduction start position of the chamfer width W1 in the chamfer section constituting the cutting edge 4, is a position at which the boundary between the cutting edge 15 and the main cutting edge 13 is thinned. Except for this, the drill 100 of the present embodiment has the same configuration as the drill of the first embodiment.
In this embodiment, the material of the workpiece is different from that of the workpiece in the first embodiment. The rotational speed N of the drill 100 is set to be higher than that of the drill of the first embodiment. In this case, the position in the tool head 3 where the cutting speed V is 50m/min is a position where the boundary between the cutting edge 15 and the main cutting edge 13 is thinned. Therefore, in the present embodiment, the position of the boundary between the thinning cutting edge 15 and the main cutting edge 13 is set as the reduction start position of the chamfer width W1 (the second position P2 in the chamfer section).
Also in the present embodiment, the value of the chamfer width W1 is constant in the entire central region in the portion of the chamfer section near the center of the tool head 3. In the present embodiment, the central region is a first region from a position (first position P1 in the chamfer section) of the end portion of the thinned cutting edge 15 near the center of the tool head 3 to a position (second position P2 in the chamfer section) of the boundary between the thinned cutting edge 15 and the main cutting edge 13 in the radial direction D3 of the drill 100. That is, the central region is the entire thinned cutting edge 15. The value of the chamfer width W1 P1 at the first position P1 and the value of the chamfer width W1 P2 at the second position P2 are the same. The reduction start position of the chamfer width W1 is set to a position between the thinning cutting edge 15 and the main cutting edge 13 that is closer to the boundary in the portion of the outer peripheral edge of the tool head 3 than the central region of the chamfer section, and the chamfer width W1 gradually decreases from the reduction start position toward the outer peripheral edge of the tool head 3. Specifically, the chamfer width W1 gradually decreases in a second region from a position of the boundary between the thinning cutting edge 15 and the main cutting edge 13 to a third position P3 in the main cutting edge 13 located at the outer peripheral edge of the tool head 3. That is, the value of the chamfer width W1 gradually decreases from the second position P2 toward the third position P3 in the main cutting edge 13. The value of the chamfer width W1 P3 at the third position P3 is smaller than the value of the chamfer width W1 P2 at the second position P2. In the drill 100 of the present embodiment, in a region from the first position P1 at the end of the chamfering section near the center of the tool head 3 to the third position P3 at the outer peripheral edge of the tool head 3 in the chamfering section, the second position P2 at which the cutting speed is the speed at which the sharp stacked edge is formed in the chamfering section is set as the reduction start position of the chamfering width W1. That is, in the drill 100 of the present embodiment, the reduction start position of the chamfer width W1 is set to the second position P2, and at this second position P2, the cutting speed is a speed at which the stacking edge becomes sharp and the sharp stacking edge continuously adheres to the chamfer section. In the drill 100 of the present embodiment, the chamfer width W1 of the cutting edge 4 gradually decreases from the reduction start position toward the outer peripheral edge of the tool head 3. This configuration achieves the same advantageous effects as the first embodiment.
(Third embodiment)
As shown in fig. 8 and 9, in the drill 200 of the present embodiment, the second position P2, which is the reduction start position of the chamfer width W1 in the chamfer section constituting the cutting edge 4, is an intermediate position in the thinning cutting edge 15. The intermediate positions in the thinning cutting edge 15 are the following predetermined positions: the predetermined position is located between a position of the end of the reduced cutting edge 15 near the center of the tool head 3 (the first position P1 in the chamfer section) and a fifth position P5, the fifth position P5 being located at the end of the reduced cutting edge 15 near the outer peripheral edge of the tool head 3 in the radial direction D3 of the drill 200. Except for this, the drill 200 of the present embodiment has the same configuration as the drill of the first embodiment.
In this embodiment, the material of the workpiece is different from those of the workpieces in the first and second embodiments. The rotational speed N of the drill 200 is set to be higher than that of the drill of the second embodiment. In this case, the position in the tool head 3 where the cutting speed V is 50m/min is an intermediate position in the thinning cutting edge 15. Therefore, in the present embodiment, the intermediate position in the thinning cutting edge 15 is set as the reduction start position of the chamfer width W1 (the second position P2 in the chamfer section).
Also in the present embodiment, the value of the chamfer width W1 is constant in the entire central region in the portion of the chamfer section near the center of the tool head 3. In the present embodiment, the central region is a first region from a position (first position P1 in the chamfer section) of the end portion of the thinned cutting edge 15 near the center of the tool head 3 to an intermediate position (second position P2 in the chamfer section) of the thinned cutting edge 15 in the radial direction D3 of the drill bit 200. That is, the chamfer width W1 P1 at the first position P1 and the chamfer width W1 P2 at the second position P2 have the same value. The reduction start position of the chamfer width W1 is set to an intermediate position in a portion of the thinning cutting edge 15 that is closer to the outer peripheral edge of the tool head 3 than the central region, and the chamfer width W1 gradually decreases from the reduction start position toward the outer peripheral edge of the tool head 3. Specifically, the chamfer width W1 gradually decreases in a second region from an intermediate position in the thinned cutting edge 15 to a fifth position P5, the fifth position P5 being located at an end of the thinned cutting edge 15 near the outer peripheral edge of the tool head 3. That is, the value of the chamfer width W1 gradually decreases from the second position P2 toward the fifth position P5 in the thinning cutting edge 15. the value of the chamfer width W1 P5 at the fifth position P5 is smaller than the value of the chamfer width W1 P2 at the second position P2. The chamfer width W1 is further reduced in a third region from the position of the boundary between the thinned cutting edge 15 and the main cutting edge 13 to a third position P3 in the main cutting edge 13 located at the peripheral edge of the tool head 3. That is, the value of the chamfer width W1 further decreases in the main cutting edge 13 from the fifth position P5 toward the third position P3. The value of the chamfer width W1 P3 at the third position P3 is smaller than the value of the chamfer width W1 P5 at the fifth position P5. In the drill 200 of the present embodiment, in a region from the first position P1 at the end of the chamfering section near the center of the tool head 3 to the third position P3 at the outer peripheral edge of the tool head 3 in the chamfering section, the second position P2 at which the cutting speed is the speed at which the sharp stacked edge is formed in the chamfering section is set as the reduction start position of the chamfering width W1. That is, in the drill 200 of the present embodiment, the reduction start position of the chamfer width W1 is set to the second position P2, at which the cutting speed is a speed at which the stacking edge becomes sharp and the sharp stacking edge continuously adheres to the chamfer section. In the drill 200 of the present embodiment, the chamfer width W1 of the cutting edge 4 gradually decreases from the reduction start position toward the outer peripheral edge of the tool head 3. This configuration achieves the same advantageous effects as the first embodiment.
(Other embodiments)
(1) In the above embodiment, the reduction start position of the chamfer width W1 is a position at which the cutting speed V in the tool head 3 is 50 m/min. However, a cutting speed V of 50m/min is merely an example. The cutting speed V may not necessarily be 50m/min as long as the cutting speed V is a speed at which the stacking edge becomes sharp and the sharp stacking edge continuously adheres to the chamfer section.
(2) In the above embodiment, the first position P1 located at the end of the reduced cutting edge 15 near the center of the tool head 3 is the position of the center C1 of the tool head 3. However, the first position P1 located at the end of the reduced cutting edge 15 near the center of the tool head 3 may be a position closer to the outer peripheral edge of the tool head 3 than the center C1 of the tool head 3 in the radial direction D3 of the drill bit 1.
(3) In the above embodiment, the cutting edge 4 includes the thinned cutting edge 15. However, the cutting edge 4 may comprise only the main cutting edge 13, and not the thinning cutting edge 15.
(4) In the above-described embodiments, the technique of the present disclosure is applied to the drill 1 as a rotary cutting tool. However, the technique of the present disclosure may also be applied to rotary cutting tools other than the drill 1 that include a cutting edge having a chamfer section. Examples of the rotary cutting tool other than the drill bit 1 include reamers and milling cutters.
(5) The present disclosure is not limited to the above-described embodiments, but may be appropriately modified within the scope of the claims. The present disclosure also includes various modifications and alterations within the equivalent scope. These embodiments are not independent of each other, but may be appropriately combined unless the combination is obviously impossible. It goes without saying that in the embodiment, elements constituting the embodiment are not necessarily necessary unless explicitly stated that these elements are necessary or are considered to be obviously necessary in principle. When a numerical value such as the number, numerical value, amount, or range of components of the embodiment is referred to in the embodiment, the numerical value is not limited to the specific number unless it is explicitly indicated that the specific number is necessary or that the numerical value is in principle clearly limited to the specific number. When referring to materials, shapes, positional relationships, and the like of components in the embodiments, the materials, shapes, positional relationships, and the like are not limited to specific materials, shapes, positional relationships, and the like, unless explicitly indicated or the materials, shapes, positional relationships, and the like are in principle limited to specific materials, shapes, positional relationships, and the like.
Claims (7)
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| JP2021027637A JP7510647B2 (en) | 2021-02-24 | 2021-02-24 | Rotary tools |
| JP2021-027637 | 2021-02-24 |
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Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2004268230A (en) * | 2003-03-11 | 2004-09-30 | Mitsubishi Materials Corp | Drill |
| JP2019171493A (en) * | 2018-03-27 | 2019-10-10 | 三菱マテリアル株式会社 | Drill |
Family Cites Families (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS60175513U (en) | 1984-05-02 | 1985-11-20 | 住友電気工業株式会社 | drill structure |
| JP3450278B2 (en) | 2000-07-24 | 2003-09-22 | 三菱マテリアル神戸ツールズ株式会社 | Drill |
| JP2007050477A (en) | 2005-08-18 | 2007-03-01 | Mitsubishi Materials Kobe Tools Corp | Drill with extra-high pressure sintered body chip |
| JP5346373B2 (en) * | 2009-06-26 | 2013-11-20 | 京セラ株式会社 | Cutting insert, cutting tool, and method of manufacturing a cut product using the same |
| JP6288585B2 (en) | 2014-06-17 | 2018-03-07 | 住友電工ハードメタル株式会社 | drill |
| JP6645964B2 (en) * | 2014-07-29 | 2020-02-14 | 京セラ株式会社 | Manufacturing method of cutting insert, cutting tool, and cut workpiece |
| US10315257B2 (en) * | 2015-05-28 | 2019-06-11 | Kyocera Corporation | Drill and method of manufacturing machined product |
| JP6725684B2 (en) * | 2016-11-15 | 2020-07-22 | 京セラ株式会社 | Rotating tool and method of manufacturing cut product using the same |
| US11311947B2 (en) * | 2017-06-02 | 2022-04-26 | Kyocera Corporation | Rotary tool |
| DE102018205681B4 (en) * | 2018-04-13 | 2023-06-15 | Kennametal Inc. | Method of manufacturing a cutting tool and cutting tool |
| CN112672840B (en) | 2018-09-12 | 2023-10-13 | 京瓷株式会社 | Cutting insert, rotary tool, and method for manufacturing cut product |
| FR3094251B1 (en) * | 2019-03-28 | 2021-04-30 | Desgranges Outils Coupants | Rotary cutting tool, such as a drill or reamer |
-
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- 2021-02-24 JP JP2021027637A patent/JP7510647B2/en active Active
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- 2022-02-21 DE DE102022104036.4A patent/DE102022104036A1/en active Pending
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2004268230A (en) * | 2003-03-11 | 2004-09-30 | Mitsubishi Materials Corp | Drill |
| JP2019171493A (en) * | 2018-03-27 | 2019-10-10 | 三菱マテリアル株式会社 | Drill |
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| JP2022129078A (en) | 2022-09-05 |
| DE102022104036A1 (en) | 2022-08-25 |
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