Rotary tool and method for producing cut workpiece

Abstract

Provided is a rotary tool capable of performing stable cutting while not readily generating chatter vibration. According to the present invention, a second twist angle and a fourth twist angle are each constant, the fourth twist angle is greater than the second twist angle, a third twist angle increases with proximity to a rear end, and the length of a third region in a direction following a rotary axis is greater than the length of a second region and greater than the length of a fourth region.

Description

Rotary tool and method for manufacturing machined product

[0001] The present disclosure relates to a rotary tool and a method for manufacturing a machined product.

[0002] Rotary tools are used for cutting workpieces, and examples of rotary tools include end mills, drills, and reamers.

[0003] Drills described in Patent Documents 1 and 2 are known as rotary tools. The drills described in Patent Documents 1 and 2 have a cutting edge located on the tip end side and a spiral flute extending from the cutting edge toward the rear end. The flutes of the drills described in Patent Documents 1 and 2 do not have a constant twist angle. These flutes have portions with small twist angles and portions with large twist angles. This improves the rigidity and chip discharge performance of the drill.

[0004] Japanese Patent Publication No. 2001-087919 and International Publication No. 2014 / 175396

[0005] A non-limiting example of a rotary tool according to the present disclosure includes a body extending from a tip end to a rear end along a rotation axis. The body includes a cutting edge located near the tip end and a spiral discharge groove extending from the cutting edge toward the rear end. The discharge groove includes a first region located near the tip end and having a first twist angle, a second region extending from the first region toward the rear end and having a second twist angle, a third region extending from the second region toward the rear end and having a third twist angle, and a fourth region extending from the third region toward the rear end and having a fourth twist angle. The second twist angle and the fourth twist angle are each constant. The fourth twist angle is greater than the second twist angle. The third twist angle increases toward the rear end. In a direction along the rotation axis, the length of the third region is greater than the length of the second region and greater than the length of the fourth region.

[0006] FIG. 1 is a view showing a first surface and a view showing a second surface, showing a schematic configuration of a rotary tool according to a first embodiment of the present disclosure; FIG. 2 is a view showing a front view of the tip, showing a schematic configuration of a rotary tool according to a first embodiment of the present disclosure; FIG. 3 is a perspective view showing a schematic configuration of a rotary tool according to a first embodiment of the present disclosure; FIG. 4 is a partial enlarged view showing a first surface and a partial enlarged view showing a second surface, showing a schematic configuration of a range IV of a rotary tool according to a first embodiment of the present disclosure; FIG. 5 is a partial enlarged perspective view showing a schematic configuration of a range IV of a rotary tool according to a first embodiment of the present disclosure; FIG. 6 is an explanatory diagram of the length of a second region in a direction along the rotation axis, and a second twist angle; FIG. 7 is an explanatory diagram of the length of a first region and the length of a third region, and the first twist angle and the third twist angle in a direction along the rotation axis; FIG. 8 is an explanatory diagram of the length of a fourth region in a direction along the rotation axis, and a fourth twist angle; FIG. 9 is a cross-sectional view illustrating the width of a discharge groove; FIG. 10 is a diagram showing three steps of a method for manufacturing a machined product according to a second embodiment of the present disclosure;

[0007] In recent years, there has been a demand for rotary tools that can withstand use under increasingly severe cutting conditions. Under such severe cutting conditions, chatter vibrations may occur even when the drills described in Patent Documents 1 and 2 are used.

[0008] The present disclosure has been made in view of the above-mentioned problems, and has an object to provide a rotary tool that is less likely to cause chatter vibrations and is capable of performing stable cutting processing.

[0009] In the rotary tool of the above embodiment, chatter vibration is unlikely to occur and stable cutting can be performed.

[0010] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The following describes an embodiment of the present disclosure. For convenience of explanation, the same reference numerals are used to designate components having the same functions as those previously described, and the description thereof may not be repeated.

[0011] [Embodiment 1] Fig. 1 shows a schematic configuration of a rotary tool 101 according to embodiment 1 of the present disclosure, with views of a first surface and a second surface. Fig. 2 shows a schematic configuration of the rotary tool 101 according to embodiment 1 of the present disclosure, with a tip 1 viewed from the front. Fig. 3 is a perspective view showing a schematic configuration of the rotary tool 101 according to embodiment 1 of the present disclosure. Fig. 4 is a partial enlarged view showing a schematic configuration of a range IV of the rotary tool 101 according to embodiment 1 of the present disclosure, with views of a first surface and a second surface. For the range IV, please refer to Fig. 3. Fig. 5 is a partial enlarged perspective view showing a schematic configuration of a range IV of the rotary tool 101 according to embodiment 1 of the present disclosure.

[0012] The leading end 1 may be the leading end of the entire rotary tool 101. The trailing end 2 may be the trailing end of the entire rotary tool 101. The first and second faces are surfaces of the rotary tool 101, and the position of the rotary tool 101 corresponding to the first face and the position of the rotary tool 101 corresponding to the second face are shifted by 90° around the rotation axis A from each other.

[0013] The rotary tool 101 may have a main body 3. The main body 3 may have a shape extending from the front end 1 to the rear end 2 along the rotation axis A. An example of such a shape is a rod shape. In this application, the term "along" does not necessarily mean that two members extend parallel to each other, but may also mean that the two members extend at an angle of 5° or less to each other.

[0014] The body 3 may have a cutting edge 4 and a discharge groove 5. The cutting edge 4 may be located on the front end 1 side of the body 3. The discharge groove 5 may extend from the cutting edge 4 toward the rear end 2. The discharge groove 5 may have a spiral shape. The cutting edge 4 may be a blade provided for cutting a workpiece. The discharge groove 5 may be a groove formed for discharging chips generated when the rotary tool 101 cuts a workpiece.

[0015] The discharge groove 5 may have a first region 6, a second region 7, a third region 8, and a fourth region 9. The first region 6 may be located on the side of the discharge groove 5 toward the leading end 1. The second region 7 may extend from the first region 6 toward the rear end 2. The third region 8 may extend from the second region 7 toward the rear end 2. The fourth region 9 may extend from the third region 8 toward the rear end 2.

[0016] FIG. 6 is an explanatory diagram of the length L2 of the second region 7 and the second twist angle θ2 in the direction along the rotation axis A. FIG. 7 is an explanatory diagram of the length L1 of the first region 6 and the length L3 of the third region 8, and the first twist angle θ1 and the third twist angle θ3 in the direction along the rotation axis A. FIG. 8 is an explanatory diagram of the length L4 of the fourth region 9 and the fourth twist angle θ4 in the direction along the rotation axis A. FIG. 6 shows a first explanatory image 1001 and a second explanatory image 1002. FIG. 7 shows a third explanatory image 1003 and a fourth explanatory image 1004. FIG. 8 shows a fifth explanatory image 1005 and a sixth explanatory image 1006.

[0017] The first region 6 has a first twist angle θ1. The second region 7 has a second twist angle θ2. The third region 8 has a third twist angle θ3. The fourth region 9 has a fourth twist angle θ4. The twist angle may be the angle of the direction in which the discharge groove 5 extends relative to the rotation axis A. More precisely, the ridgeline between the discharge groove 5 and the outer peripheral surface of the main body 3 located rearward of the discharge groove 5 in the rotation direction of the rotation axis A may be identified, and the angle of this ridgeline relative to the rotation axis A may be evaluated as the "twist angle."

[0018] The first twist angle θ1 may be constant or may vary with position along the axis of rotation A.

[0019] The second twist angle θ2 and the fourth twist angle θ4 may each be constant. The fourth twist angle θ4 may be greater than the second twist angle θ2. The third twist angle θ3 may increase toward the rear end 2. In the direction along the rotation axis A, the length L3 of the third region 8 may be greater than the length L2 of the second region 7 and greater than the length L4 of the fourth region 9.

[0020] Because the second twist angle θ2 is small, the rigidity of the rotary tool 101 is high. Because the fourth twist angle θ4 is large, the chip discharge performance of the rotary tool 101 is high. Because the third twist angle θ3 increases toward the rear end 2, the chips can be smoothly guided in the order of the second region 7, the third region 8, and the fourth region 9.

[0021] If the third torsion angle θ3 is not constant, the shape of the cross section of the third region 8 perpendicular to the rotation axis A will not be constant, which may result in chatter vibrations originating from the third region 8. For this reason, the length L3 of the third region 8 is set to be greater than the length L2 of the second region 7 and greater than the length L4 of the fourth region 9. This reduces the amount of change in the shape of the cross section of the third region 8 perpendicular to the rotation axis A depending on the position along the rotation axis A, thereby reducing the risk of chatter vibrations originating from the third region 8.

[0022] From the above viewpoint, it is possible to realize a rotary tool 101 that is less likely to cause chatter vibration and is capable of performing stable cutting processing.

[0023] The length L2 of the second region 7 may be smaller than the length L4 of the fourth region 9 in the direction along the rotation axis A. This improves chip discharge performance. Furthermore, the length L2 of the second region 7 may be larger than the length L4 of the fourth region 9 in the direction along the rotation axis A. This increases the area of ​​the rotary tool 101 that contributes to high rigidity, thereby further increasing the rigidity of the rotary tool 101.

[0024] The maximum value of the first twist angle θ1 may be greater than the maximum value of the third twist angle θ3 and greater than the fourth twist angle θ4. In this case, the maximum value of the first twist angle θ1 may of course be greater than the second twist angle θ2. This allows chips to be smoothly guided to the second region 7. When the first twist angle θ1 and the third twist angle θ3 are not constant and change depending on the position along the rotation axis A, their respective maximum values ​​may be used. On the other hand, when the first twist angle θ1 is constant, this constant value may be considered as the maximum value of the first twist angle θ1. Furthermore, because the second twist angle θ2 and the fourth twist angle θ4 may each be constant depending on the position along the rotation axis A, their maximum values ​​may not be used.

[0025] In the direction along the rotation axis A, the length L2 of the second region 7 may be greater than the length L1 of the first region 6. This allows the area that contributes to high rigidity in the rotary tool 101 to be larger, thereby making it possible to further increase the rigidity of the rotary tool 101.

[0026] The width W3 of the third region 8 may increase circumferentially around the rotation axis A toward the rear end 2. In the third region 8, where the twist angle changes, the direction of chip movement is likely to change, making the flow of chips prone to stagnation. However, with the above-described configuration, the flow of chips in the third region 8 is smooth, making chip clogging less likely to occur.

[0027] In the circumferential direction of the rotation axis A, the width W2 of the second region 7 may be smaller than the width W4 of the fourth region 9. This makes it easier to ensure the thickness of the main body 3 at the location where the second region 7 is provided, which is located closer to the tip than the fourth region 9. As a result, the rigidity of the rotary tool 101 is increased.

[0028] 9 is a cross-sectional view illustrating the width W of the discharge groove 5. The width W of the discharge groove 5 may be the length of the opening 51 of the discharge groove 5 in a cross-sectional view of the discharge groove 5.

[0029] The main body 3 may have a cutting insert 10 and a holder 11. The cutting insert 10 may be located on the front end 1 side of the main body 3. The holder 11 may be located on the rear end 2 side of the cutting insert 10. The cutting insert 10 may be attached to the holder 11. The first region 6 may be located in the cutting insert 10. The second region 7 may be located in the holder 11.

[0030] Examples of materials for the cutting insert 10 include cemented carbide and cermet.

[0031] Examples of cemented carbide compositions include WC-Co, WC-TiC-Co, and WC-TiC-TaC-Co. WC-Co may be produced by adding cobalt (Co) powder to tungsten carbide (WC) and sintering the mixture. WC-TiC-Co may be produced by adding titanium carbide (TiC) to WC-Co. WC-TiC-TaC-Co may be produced by adding tantalum carbide (TaC) to WC-TiC-Co.

[0032] The cermet may be a sintered composite material in which a ceramic component is combined with a metal. Specifically, the cermet may be a cermet containing a titanium compound as a main component. Examples of the cermet containing a titanium compound as a main component include titanium carbide (TiC) and titanium nitride (TiN).

[0033] Examples of materials for the holder 11 include aluminum, carbon steel, alloy steel, stainless steel, cast iron, and non-ferrous metals.

[0034] The main body 3 may have a cutting portion 52 including the cutting blade 4 for cutting a workpiece, and a gripping portion 53 for gripping the rotary tool 101 .

[0035] The maximum value of the first twist angle θ1 may be within a range of 15° to 40°, the second twist angle θ2 may be within a range of 5° to 30°, the third twist angle θ3 may be within a range of 5° to 35°, and the fourth twist angle θ4 may be within a range of 10° to 30°.

[0036] The length L1 of the first region 6 may be within a range of 5% to 25% of the length of the discharge groove 5 in the direction along the rotation axis A. The length L2 of the second region 7 may be within a range of 20% to 20% of the length of the discharge groove 5 in the direction along the rotation axis A. The length L3 of the third region 8 may be within a range of 30% to 50% of the length of the discharge groove 5 in the direction along the rotation axis A. The length L4 of the fourth region 9 may be within a range of 15% to 35% of the length of the discharge groove 5 in the direction along the rotation axis A.

[0037] The width W2 of the second region 7 may be in the range of 5 mm to 20 mm, the width W3 of the third region 8 may be in the range of 5 mm to 20 mm, and the width W4 of the fourth region 9 may be in the range of 5 mm to 20 mm.

[0038] 10 is a diagram illustrating three steps of a method for manufacturing a machined product 301 according to a second embodiment of the present disclosure. The method for manufacturing the machined product 301 may include steps D1 to D3. The machined product 301 may be obtained upon completion of step D3.

[0039] Step D1 is a step of rotating the rotary tool 101 around the rotation axis A. Step D2 is a step of bringing the cutting edge 4 of the rotating rotary tool 101 into contact with the workpiece 201. Step D3 is a step of separating the rotary tool 101 from the workpiece 201. Examples of materials for the workpiece 201 include carbon steel, alloy steel, stainless steel, cast iron, and non-ferrous metals.

[0040] In each of steps D2 and D3, the rotary tool 101 and the workpiece 201 (machined object 301) may be moved relatively. In this case, the rotary tool 101 may be moved, the workpiece 201 (machined object 301) may be moved, or both the rotary tool 101 and the workpiece 201 (machined object 301) may be moved. In step D2, a hole (perforation) 151 may be made in the workpiece 201 by the cutting blade 4.

[0041] According to the manufacturing method of the machined product 301, the machined product 301 is manufactured using the rotary tool 101 that is less susceptible to chatter vibration and is capable of performing stable cutting. Therefore, according to the manufacturing method of the machined product 301, the workpiece 201 can be cut with excellent machining accuracy, and the machined product 301 having a highly accurate machined surface can be obtained.

[0042] 〔summary〕 A rotary tool according to a first aspect of the present disclosure has a main body having a shape extending from a tip end to a rear end along a rotation axis, the main body having a cutting edge located on the tip side and a spiral discharge groove extending from the cutting edge towards the rear end, the discharge groove having a first region located on the tip side and having a first twist angle, a second region extending from the first region towards the rear end and having a second twist angle, a third region extending from the second region towards the rear end and having a third twist angle, and a fourth region extending from the third region towards the rear end and having a fourth twist angle, the second twist angle and the fourth twist angle being constant, the fourth twist angle being greater than the second twist angle, and the third twist angle increasing towards the rear end, and the length of the third region being greater than the length of the second region and the length of the fourth region in a direction along the rotation axis.

[0043] A rotary tool according to a second aspect of the present disclosure is the rotary tool of the first aspect, wherein the length of the second region is greater than the length of the fourth region in the direction along the rotation axis.

[0044] A rotary tool according to a third aspect of the present disclosure is the rotary tool of the first or second aspect, wherein the maximum value of the first twist angle is greater than the maximum value of the third twist angle and greater than the fourth twist angle.

[0045] A rotary tool according to a fourth aspect of the present disclosure is the rotary tool of the third aspect, wherein the length of the second region is greater than the length of the first region in the direction along the rotation axis.

[0046] A rotary tool according to a fifth aspect of the present disclosure is in any one of the first to fourth aspects, wherein the width of the third region increases in the circumferential direction of the rotary shaft toward the rear end.

[0047] A rotary tool according to a sixth aspect of the present disclosure is the rotary tool of any one of the first to fifth aspects, wherein the width of the second region is smaller than the width of the fourth region in the circumferential direction of the rotation shaft.

[0048] A rotary tool according to aspect 7 of the present disclosure is a rotary tool according to any one of aspects 1 to 6, wherein the main body has a cutting insert located on the tip side and a holder located on the rear end side of the cutting insert and to which the cutting insert is attached, and the first region is located on the cutting insert and the second region is located on the holder.

[0049] A method for manufacturing a machined product according to aspect 8 of the present disclosure is, in any one of aspects 1 to 7, a method for manufacturing a machined product, which includes the steps of rotating the rotary tool around the rotation axis, bringing the cutting edge of the rotating rotary tool into contact with a workpiece, and moving the rotary tool away from the workpiece.

[0050] The invention according to the present disclosure has been described above based on the drawings and examples. However, the invention according to the present disclosure is not limited to the above-described embodiments. In other words, the invention according to the present disclosure can be modified in various ways within the scope of the present disclosure, and embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the invention according to the present disclosure. In other words, it should be noted that a person skilled in the art could easily make various modifications or corrections based on the present disclosure. It should also be noted that these modifications or corrections are included in the scope of the present disclosure.

[0051] REFERENCE SIGNS LIST 1 Tip 2 Rear end 3 Body 4 Cutting edge 5 Discharge groove 6 First region 7 Second region 8 Third region 9 Fourth region 10 Cutting insert 11 Holder 101 Rotary tool 201 Workpiece 301 Machined product A Rotary shaft L1 Length of first region L2 Length of second region L3 Length of third region L4 Length of fourth region W2 Width of second region W3 Width of third region W4 Width of fourth region θ1 First twist angle θ2 Second twist angle θ3 Third twist angle θ4 Fourth twist angle

Claims

1. A cutting tool having a body extending from a leading end to a trailing end along a rotation axis, the body having a cutting edge located on the leading end side, and a spiral discharge groove extending from the cutting edge towards the trailing end, the discharge groove having: a first region located on the leading end side and having a first twist angle; a second region extending from the first region towards the trailing end and having a second twist angle; a third region extending from the second region towards the trailing end and having a third twist angle; and a fourth region extending from the third region towards the trailing end and having a fourth twist angle, the second twist angle and the fourth twist angle being constant, the fourth twist angle being greater than the second twist angle, and the third twist angle increasing as the groove approaches the trailing end, a length of the third region in a direction along the rotation axis that is greater than a length of the second region and greater than a length of the fourth region.

2. The rotary tool according to claim 1, wherein the length of the second region is greater than the length of the fourth region in the direction along the rotation axis.

3. The rotary tool according to claim 1 or 2, wherein the maximum value of the first twist angle is greater than the maximum value of the third twist angle and greater than the maximum value of the fourth twist angle.

4. The rotary tool according to claim 3, wherein the length of the second region is greater than the length of the first region in the direction along the rotation axis.

5. A rotary tool according to any one of claims 1 to 4, wherein the width of the third region increases in the circumferential direction of the rotary shaft as it approaches the rear end.

6. A rotary tool according to any one of claims 1 to 5, wherein the width of the second region is smaller than the width of the fourth region in the circumferential direction of the rotary shaft.

7. A rotary tool according to any one of claims 1 to 6, wherein the main body has a cutting insert located on the front end side, and a holder located on the rear end side of the cutting insert and to which the cutting insert is attached, the first region being located on the cutting insert, and the second region being located on the holder.

8. A method for manufacturing a machined product, comprising the steps of: rotating the rotary tool according to any one of claims 1 to 7 around the rotation axis; bringing the cutting edge of the rotating rotary tool into contact with a workpiece; and removing the rotary tool from the workpiece.

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