Drill and method for producing cut workpiece

Abstract

Provided is a drill that makes it possible to improve chip discharge capability and cutting capability. A second thinning surface of the drill includes a first region having a concave curved surface shape, and a flat second region positioned closer to the outer peripheral side than the first region. The drill is such that the second region is connected to a second blade and the first region is separated from the second blade.

Description

Drill and cutting process

[0001] The present disclosure relates to methods of manufacturing drills and cuttings.

[0002] Examples of drills used in cutting workpieces such as metals include drills described in Patent Documents 1 and 2. The drills described in Patent Documents 1 and 2 each have multiple thinning surfaces. Each thinning surface is flat or concavely curved. By providing such thinning surfaces, the drill is able to improve its bite into the workpiece and its chip discharge.

[0003] International Publication No. WO 2019 / 031737 International Publication No. WO 2019 / 176452

[0004] In one non-limiting aspect of the present disclosure, the drill has a shape that can rotate around a rotation axis and a body that extends from a front end to a rear end along the rotation axis. The body has a cutting edge located on the front end side and an ejection flute that extends from the cutting edge toward the rear end. The cutting edge has a first cutting edge, a second cutting edge located outer circumferentially of the first cutting edge, and a third cutting edge located outer circumferentially of the second cutting edge. The ejection flute has a first concave thinning surface that extends from the first cutting edge toward the rear end and a second thinning surface that extends from the second cutting edge toward the rear end. The second thinning surface has a first region that has a concave curved shape and a flat second region that is located outer circumferentially of the first region. The second region is connected to the second cutting edge, and the first region is spaced apart from the second cutting edge.

[0005] FIG. 7 is a perspective view showing a schematic configuration of a drill according to embodiment 1 of the present disclosure. FIG. 8 is a partially enlarged perspective view showing a schematic configuration of a range II of the drill according to embodiment 1 of the present disclosure. FIG. 9 is a front view of the tip showing a schematic configuration of the drill according to embodiment 1 of the present disclosure. FIG. 10 is a partially enlarged view showing a schematic configuration of a range IV of the first cutting edge and the second cutting edge. FIG. 11 is a front view of the first surface showing a schematic configuration of the drill according to embodiment 1 of the present disclosure. FIG. 12 is a front view of the second surface showing a schematic configuration of the drill according to embodiment 1 of the present disclosure. FIG. 13 is a partially enlarged view showing a schematic configuration of a range VII of the drill according to embodiment 1 of the present disclosure. FIG. 14 is a partially enlarged view showing a schematic configuration of a range VIII of the drill according to embodiment 1 of the present disclosure. FIG. 15 is a cross-sectional view taken along line IX-IX of FIG. 7. FIG. 16 is three front views showing a method for manufacturing a machined product according to embodiment 2 of the present disclosure.

[0006] In recent years, drills have been required to further improve their machining efficiency, and drills that can withstand machining conditions with higher cutting loads are needed. In the drill described in Patent Document 1, chips flowing along the flat thinning surface may proceed into the flute without properly curling, which may result in reduced chip discharge. In the drill described in Patent Document 2, only one of the multiple thinning surfaces is connected to the cutting edge, which imposes restrictions on the shape of the cutting edge. This may make it difficult to improve the machinability of the workpiece.

[0007] In the drill of the above embodiment, it is possible to improve chip discharge performance and cutting performance.

[0008] 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.

[0009] [Embodiment 1] Fig. 1 is a perspective view showing a schematic configuration of a drill 101 according to embodiment 1 of the present disclosure. Fig. 2 is a partially enlarged perspective view showing a schematic configuration of range II of the drill 101 according to embodiment 1 of the present disclosure. Fig. 3 is a front view of the tip 1 showing a schematic configuration of the drill 101 according to embodiment 1 of the present disclosure. Fig. 4 is a partially enlarged view showing a schematic configuration of range IV of the first cutting edge 6 and the second cutting edge 7. Please refer to Fig. 1 for range II and Fig. 3 for range IV.

[0010] FIG. 5 is a front view of a first surface showing a schematic configuration of the drill 101 according to the first embodiment of the present disclosure. FIG. 6 is a front view of a second surface showing a schematic configuration of the drill 101 according to the first embodiment of the present disclosure. FIG. 7 is a partially enlarged view showing a schematic configuration of a range VII of the drill 101 according to the first embodiment of the present disclosure. FIG. 8 is a partially enlarged view showing a schematic configuration of a range VIII of the drill 101 according to the first embodiment of the present disclosure. FIG. 9 is a cross-sectional view taken along line IX-IX of FIG. 7. Please refer to FIG. 5 for the range VII and FIG. 6 for the range VIII.

[0011] The leading end 1 may be the leading end of the entire drill 101. The trailing end 2 may be the trailing end of the entire drill 101. The first and second faces are surfaces of the drill 101, and the position of the drill 101 corresponding to the first face and the position of the drill 101 corresponding to the second face are shifted by 90° around the rotation axis A from each other.

[0012] The drill 101 may have a body 3. The body 3 may be rotatable about a rotation axis A. The body 3 may be shaped to extend from the tip 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.

[0013] The body 3 may have a cutting edge 4 and a discharge groove 5. The cutting edge 4 may be located on the side of the tip 1. The discharge groove 5 may extend from the cutting edge 4 toward the rear end 2. 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 drill 101 cuts a workpiece. The body 3 may further have a flank 1a located on the side of the tip 1. The flank 1a intersects with the discharge groove 5. The cutting edge 4 may be located at the intersection of the flank 1a and the discharge groove 5.

[0014] The cutting edge 4 may have a first edge 6, a second edge 7, and a third edge 8. The second edge 7 may be located closer to the outer periphery of the drill 101 than the first edge 6. The third edge 8 may be located closer to the outer periphery of the drill 101 than the second edge 7.

[0015] The cutting edge 4 may extend to the tip 1 or may be spaced apart from the tip 1. As shown in an example in Figures 3 and 4, a chisel edge 1b may be present from the cutting edge 4 toward the tip 1 (rotation axis A).

[0016] The discharge groove 5 may have a first thinning surface 9 and a second thinning surface 10. The first thinning surface 9 may extend from the first cutting edge 6 toward the rear end 2. The first thinning surface 9 may be concave. The second thinning surface 10 may extend from the second cutting edge 7 toward the rear end 2.

[0017] The second thinning surface 10 may have a first region 11 and a second region 12. The first region 11 may have a concave curved surface shape. The second region 12 may be located closer to the outer periphery of the drill 101 than the first region 11. The second region 12 may be flat.

[0018] The drill 101 may have the second region 12 connected to the second cutting edge 7 and the first region 11 spaced apart from the second cutting edge 7 .

[0019] The drill 101 has high chip discharge performance because chips flowing through the first region 11 curl appropriately and proceed through the discharge flute 5. The drill 101 has both the first thinning surface 9 and the second thinning surface 10 connected to the cutting edge 4, which places little constraint on the shape of the cutting edge 4. This makes it easy to improve the machinability of the workpiece.

[0020] When the first region 11 is connected to the second blade 7, the curved first region 11 reaches the tip 1 and connects to the cutting edge 4. This causes the second blade 7 to be significantly curved in correspondence with the first region 11. Therefore, the boundary between the first blade 6 and the second blade 7 is likely to be sharp, and chipping of the cutting edge 4 may occur easily.

[0021] When the first region 11 is spaced apart from the second blade 7, only the flat second region 12 reaches the tip 1 and connects to the cutting edge 4. This reduces the curvature of the second blade 7. Therefore, the boundary between the first blade 6 and the second blade 7 is less likely to be sharp, and chipping of the cutting edge 4 is less likely to occur.

[0022] From the above viewpoints, the drill 101 can improve chip discharge performance and cutting performance.

[0023] The discharge groove 5 may further have a third thinning surface 13. The third thinning surface 13 may be located closer to the rear end 2 than the first thinning surface 9 and the second thinning surface 10. The third thinning surface 13 may have a concave shape. In the drill 101, the first region 11 may be connected to the third thinning surface 13, and the second region 12 may be spaced apart from the third thinning surface 13. This makes it easy to guide chips to the third thinning surface 13 via the first region 11, thereby improving chip discharge performance.

[0024] The angle θ formed by the ridge line 14 located at the intersection of the first thinning surface 9 and the third thinning surface 13 and the ridge line 15 located at the intersection of the second thinning surface 10 and the third thinning surface 13 may be an obtuse angle. This prevents the end of the first region 11 on the third thinning surface 13 side from facing the tip 1, thereby reducing the risk of chips being returned from the first region 11 to the tip 1 side. This allows for improved chip removal and cutting performance.

[0025] The discharge groove 5 may further have a main groove 16. The main groove 16 may extend spirally from the third cutting edge 8 toward the rear end 2. The first region 11 and the second region 12 in the second thinning surface 10 may each be connected to the main groove 16. This makes it easy to guide chips to the main groove 16, thereby improving chip discharge performance.

[0026] The area of ​​the second region 12 may be larger than the area of ​​the first region 11. This makes it difficult for chips to clog the first region 11, which has a concave curved surface shape, and chip discharge performance is likely to be improved.

[0027] The first blade 6 may have a concave shape when viewed from the direction along the rotation axis A, and a straight shape when viewed from the front in the rotation direction of the rotation axis A. The second blade 7 may have a straight shape when viewed from the direction along the rotation axis A, and a concave shape when viewed from the front in the rotation direction of the rotation axis A. This allows the point angle of the first blade 6 to be small, improving the bite into the workpiece.

[0028] The main body 3 may have a cutting insert 51 and a holder 52. The cutting insert 51 may be located on the front end 1 side of the main body 3. The holder 52 may be located on the rear end 2 side of the cutting insert 51. The cutting insert 51 may be attached to the holder 52.

[0029] Examples of the material of the cutting insert 51 include cemented carbide and cermet.

[0030] 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.

[0031] 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).

[0032] Examples of materials for the holder 52 include aluminum, carbon steel, alloy steel, stainless steel, cast iron, and non-ferrous metals.

[0033] The body 3 may have a cutting portion 53 including the cutting edge 4 for cutting a workpiece, and a gripping portion 54 for gripping the drill 101. According to Fig. 4, the first cutting edge 6 may have a concave curved shape. According to Fig. 4, the second cutting edge 7 may have a substantially straight shape.

[0034] 10 is a diagram illustrating three front views 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. Upon completion of step D3, the machined product 301 may be obtained.

[0035] Step D1 is a step of rotating the drill 101. Step D2 is a step of bringing the drill 101 into contact with the workpiece 201. Step D3 is a step of separating the drill 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.

[0036] In each of steps D2 and D3, the drill 101 and the workpiece 201 (machined workpiece 301) may be moved relative to each other. In this case, the drill 101 may be moved, the workpiece 201 (machined workpiece 301) may be moved, or both the drill 101 and the workpiece 201 (machined workpiece 301) may be moved. In step D2, a hole (perforation) 151 may be drilled in the workpiece 201 by the cutting edge 4.

[0037] According to the manufacturing method of the machined product 301, the drill 101 capable of improving chip discharge performance and cutting performance is used to manufacture the machined product 301. 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.

[0038] [Summary] A drill according to aspect 1 of the present disclosure has a shape that is rotatable around a rotation axis and has a body extending from a front end to a rear end along the rotation axis, the body having a cutting edge located on the front end side and an ejection groove extending from the cutting edge toward the rear end, the cutting edge having a first blade, a second blade located outer circumferentially of the first blade, and a third blade located outer circumferentially of the second blade, the ejection groove having a first concave thinning surface extending from the first blade toward the rear end and a second thinning surface extending from the second blade toward the rear end, the second thinning surface having a first region having a concave curved shape and a flat second region located outer circumferentially of the first region, the second region being connected to the second blade and the first region being spaced apart from the second blade.

[0039] A drill according to aspect 2 of the present disclosure is similar to aspect 1 in that the discharge groove further has a concave third thinning surface located closer to the rear end than the first thinning surface and the second thinning surface, and the first region is connected to the third thinning surface and the second region is spaced apart from the third thinning surface.

[0040] The drill according to aspect 3 of the present disclosure is the drill according to aspect 2, wherein the angle formed by the ridge line located at the intersection of the first thinning surface and the third thinning surface and the ridge line located at the intersection of the second thinning surface and the third thinning surface is an obtuse angle.

[0041] A drill according to aspect 4 of the present disclosure is any one of aspects 1 to 3, wherein the discharge groove further has a main groove extending spirally from the third cutting edge toward the rear end, and the first region and the second region in the second thinning surface are each connected to the main groove.

[0042] A drill according to a fifth aspect of the present disclosure is any one of the first to fourth aspects, wherein the area of ​​the second region is larger than the area of ​​the first region.

[0043] A drill according to aspect 6 of the present disclosure is any one of aspects 1 to 5, wherein the first cutting edge is concave when viewed from a direction along the rotation axis and linear when viewed from the front in the direction of rotation of the rotation axis, and the second cutting edge is linear when viewed from a direction along the rotation axis and concave when viewed from the front in the direction of rotation of the rotation axis.

[0044] A method for manufacturing a machined product according to aspect 7 of the present disclosure includes, in any one of aspects 1 to 6, the steps of rotating the drill, bringing the drill into contact with a workpiece, and removing the drill from the workpiece.

[0045] 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.

[0046] REFERENCE SIGNS LIST 1 Tip 2 Rear end 3 Body 4 Cutting edge 5 Discharge groove 6 First cutting edge 7 Second cutting edge 8 Third cutting edge 9 First thinning surface 10 Second thinning surface 11 First region 12 Second region 13 Third thinning surface 14, 15 Ridge line 16 Main groove 101 Drill 201 Workpiece 301 Cutting workpiece A Rotation axis θ Angle formed by the ridge line located at the intersection of the first thinning surface and the third thinning surface and the ridge line located at the intersection of the second thinning surface and the third thinning surface

Claims

1. A drill having a shape that can rotate around a rotation axis and having a body extending from a front end to a rear end along the rotation axis, wherein the body has a cutting edge located on the front end side and an ejection groove extending from the cutting edge toward the rear end, wherein the cutting edge has a first blade, a second blade located more outer circumferentially than the first blade, and a third blade located more outer circumferentially than the second blade, wherein the ejection groove has a first concave thinning surface extending from the first blade toward the rear end and a second thinning surface extending from the second blade toward the rear end, wherein the second thinning surface has a first region having a concave curved shape and a flat second region located more outer circumferentially than the first region, wherein the second region is connected to the second blade and the first region is spaced apart from the second blade.

2. A drill as described in claim 1, wherein the discharge groove further has a concave third thinning surface located closer to the rear end than the first thinning surface and the second thinning surface, and the first region is connected to the third thinning surface, and the second region is spaced apart from the third thinning surface.

3. A drill as described in claim 2, wherein the angle formed by the ridge line located at the intersection of the first thinning surface and the third thinning surface and the ridge line located at the intersection of the second thinning surface and the third thinning surface is an obtuse angle.

4. A drill according to any one of claims 1 to 3, wherein the discharge groove further has a main groove extending spirally from the third cutting edge toward the rear end, and the first region and the second region in the second thinning surface are each connected to the main groove.

5. A drill according to any one of claims 1 to 4, wherein the area of ​​the second region is larger than the area of ​​the first region.

6. A drill as claimed in any one of claims 1 to 5, wherein the first cutting edge is concave when viewed from a direction along the rotation axis and linear when viewed from the front in the direction of rotation of the rotation axis, and the second cutting edge is linear when viewed from the direction along the rotation axis and concave when viewed from the front in the direction of rotation of the rotation axis.

7. A method for manufacturing a machined product, comprising the steps of: rotating the drill according to any one of claims 1 to 6; bringing the drill into contact with a workpiece; and separating the drill from the workpiece.

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