JP2013208694A - Drill and method for manufacturing cutting workpiece using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a drill capable of machining with high accuracy in a hole position.SOLUTION: A drill includes a columnar cutting part including: a first chisel edge and a second chisel edge positioned to be continuous to each other at a tip; a first cutting blade having one end continuous to the first chisel edge; a second cutting blade having one end continuous to a second chisel edge; a first groove continuous to the first cutting blade and spirally extended toward a rear end; a second groove continuous to the second cutting blade and spirally extended toward the rear end; a first outer peripheral part continuous to the other end of the cutting blade and extended to the second groove along an outer edge in a tip view; and a second outer peripheral part continuous to the other end of the second cutting blade and extended to the first groove along the outer edge in the tip view. In the tip view, the second outer peripheral part is recessed by a depth D2 on a rotational axis side of the cutting part with respect to the outer edge in the whole area along the outer edge of the cutting part.

Description

  The present invention relates to a drill and a method of manufacturing a cut product using the drill.

  Conventionally, for example, Patent Document 1 discloses a first cutting edge that continues to a pair of chisel edges and extends to the outer peripheral end of the drill body, and a length that is shorter in the direction along the cutting edge than the first cutting edge. A two-edged drill comprising two cutting blades is disclosed. And the structure by which the two main grooves and the two lands connected with it were provided from the front-end | tip of the drill main body corresponding to the two blades is disclosed.

  However, the two lands have a configuration in which the drill is guided by sliding contact with the inner wall of the work hole of the work material. For this reason, if the two cutting blades are shaken in the initial stage of drilling the work material, the work is performed in a state of being inclined with respect to the work material or in a state of displacement. End up. Therefore, as a result, there is a possibility that the processed hole cannot be accurately formed at a desired position.

  Therefore, a drill capable of processing with high hole position accuracy and a method of manufacturing a cut product using the drill have been demanded.

JP 2010-162644 A

  A drill according to an embodiment of the present invention includes: a first chisel edge and a second chisel edge that are continuously located at a tip portion; a first cutting edge having one end continuous with the first chisel edge; A second cutting edge that is continuous with the second chisel edge; a first groove that is continuous with the first cutting edge and extends spirally toward the rear end; and is continuous with the second cutting edge. A second groove extending spirally toward the rear end, and continuing to the other end of the first cutting edge, and extending to the second groove along the outer edge in a front end view. A cylindrical cutting part having a first outer peripheral part and a second outer peripheral part that is continuous with the other end of the second cutting edge and extends to the first groove along the outer edge in a front end view. And the second outer peripheral portion is along the outer edge of the cutting portion in a front end view. In the entire region, the outer edge is recessed with a depth D2 on the rotating shaft side of the cutting portion.

  According to an embodiment of the present invention, there is provided a manufacturing method of a cut product, the step of rotating the drill around a rotation axis, the first cutting edge and the second cutting edge of the rotating drill, And a step of separating the work material from the drill.

  According to the drill according to the embodiment of the present invention, in the front end view, the second outer peripheral portion has a depth D2 on the rotating shaft side of the cutting portion with respect to the outer edge in the entire region along the outer edge of the cutting portion. In the drilling process, a gap is generated between the second outer peripheral part and the work hole inner wall of the work material, and the second outer peripheral part side of the drill is not supported by the process hole inner wall. . Thereby, the gap that exists between the second outer peripheral portion and the inner wall of the machining hole as described above can function as a space for correcting the traveling direction of the drill by the centripetal action that acts on the drill during drilling, As a result, the hole position accuracy can be improved.

It is a figure which shows the drill which concerns on embodiment of this invention, (a) is a whole side view, (b) is the front view seen from the front-end | tip part side, (c) is a perspective view. It is the elements on larger scale which show the front-end | tip part side among the cutting parts of the drill shown in FIG. 1, (a) is the side view seen from arrow A, (b) is the side view seen from arrow B. It is the elements on larger scale which show the front-end | tip part side among the cutting parts of the drill shown in FIG. 1, (a) is the side view seen from arrow C, (b) is the side view seen from arrow D. FIG. 2 is an enlarged front view showing FIG. It is sectional drawing of the drill shown to Fig.3 (a), (a) is an AA sectional view, (b) is a BB sectional drawing. It is the elements on larger scale of the drill shown in FIG. 1, (a) is a figure which shows the area | region enclosed with the broken line of Fig.2 (a), (b) is the area | region enclosed with the broken line of FIG.2 (b). FIG. It is a figure which shows the modification of the drill which concerns on embodiment of this invention, Comprising: It is the front view which looked at the cutting part from the front-end | tip part side. It is a figure which shows the modification of the drill which concerns on embodiment of this invention, Comprising: It is the front view which looked at the cutting part from the front-end | tip part side. It is a figure which shows the modification of the drill which concerns on embodiment of this invention, Comprising: (a) is the elements on larger scale which show the site | part similar to Fig.6 (a), (b) is the site | part similar to FIG.6 (b). FIG. It is a figure explaining the manufacturing method of the cut workpiece which concerns on embodiment of this invention, (a) is a figure which shows the process of making a drill approach a Y direction toward a workpiece, (b) is a figure which covers a drill. It is a figure which shows the process made to contact a cutting material, (c) is a figure which shows the process of separating a drill from a work material in a Z direction.

<Drill>
Hereinafter, a drill according to an embodiment of the present invention will be described in detail with reference to FIGS.

  As shown in FIG. 1A, a drill 1 of the present embodiment is roughly composed of a main body 20 that is gripped by a rotating spindle or the like of a machine tool, and a cutting portion 10 provided on one end side of the main body 20. And. The main body 20 is a part designed according to the shape of the rotating shaft of the machine tool. The cutting unit 10 is a part that contacts the work material 30. The arrow a indicates the direction of rotation of the drill 1.

  The cutting part 10 is a part having a main role in the cutting of the work material 30. Specifically, the distal end portion 10a has two cutting blades 11 (a first cutting blade 11a and a second cutting blade 11b) that are positioned apart from each other via a pair of chisel edges 11a1 and 11b1 described later. In addition, two grooves 12 (a first groove 12a and a second groove 12b) are provided on the outer edge (outer periphery) 10c of the cutting portion 10 corresponding to the two cutting edges 11 from the front end portion 10a to the rear end portion 10b. doing. That is, this embodiment is a so-called two-blade drill. In addition, the outer edge (outer periphery) 10c of the cutting part 10 is shown as the continuous line in FIG.1 (b), FIG.4, and FIG.5. Moreover, in this embodiment, the shape of the cutting part 10 is a column shape. That is, in the cross section perpendicular to the rotation axis O, the cutting portion 10 has a relationship T1 and T2 where T1 is a diameter at the tip portion 10a and T2 is a diameter at a portion other than the tip portion 10a. doing. Further, the diameter of the cutting portion 10 is constant from the front end portion 10a to the rear end portion 10b in a cross section perpendicular to the rotation axis O. Here, in this specification, the rotation axis O is a line passing through the center of the cutting part 10 in the front end view and passing through a point where the pair of chisel edges 11a1 and 11b1 are continuous.

  The two cutting edges 11 are formed in the front-end | tip part 10a of the cutting part 10, as shown in FIG. In this embodiment, the 1st cutting edge 11a and the 2nd cutting edge 11b are located in the site | part of the rotational symmetry of about 180 degrees on the basis of the rotating shaft O (axis line) of the cutting part 10. FIG. Here, the length of the second cutting edge 11b is configured to be shorter than the length of the first cutting edge 11a. Specifically, one end 11aa of the first cutting edge 11a is continuous with the first chisel edge 11a1, and the other end 11ab is located on the outer edge 10c of the cutting portion 10, whereas the second cutting edge 11b One end 11ba is continuous with the second chisel edge 11b1, and the other end 11bb is located inside the outer edge 10c of the cutting portion 10. Further, as will be described later, a third cutting edge 11c is further provided that is located at the intersection of the end portion 16b11 of the second margin 16b1 and the second groove 12b adjacent to the end portion 16b11. Here, the terminator 16b11 means not a simple point / line but a predetermined area or space as shown in FIG. According to this, for example, burrs or the like remaining on the inner wall of the processed hole 31 after the drilling by the first cutting edge 11a and the second cutting edge 11b located at the tip portion 10a can be effectively removed, The smoothness of the inner wall of the processed hole 31 can be improved. Here, the first flank 14a1 that is continuous with the first cutting edge 11a is inclined, for example, 5 degrees to 15 degrees toward the rear end 10b with respect to the first cutting edge 11a, and is formed on the first flank 14a1. The continuous second flank 14a2 may be set so as to incline toward the rear end portion 10b, for example, 5 degrees to 40 degrees with respect to the first flank 14a1. The same applies to the flank 14 (the third flank 14b1 and the fourth flank 14b2) continuous with the second cutting edge 11b.

  As shown in FIGS. 1 to 4, the two chisel edges (first chisel edge 11a1 and second chisel edge 11b1) are located on the most distal end portion 10a side of the cutting portion 10, and include the first cutting edge 11a and the second cutting edge. It has a role which cuts the cut material 30 with the blade 11b. The first chisel edge 11a1 and the second chisel edge 11b1 are positioned so as to be 180 ° rotationally symmetric with respect to the rotation axis O (axis line) of the cutting portion 10. That is, the first chisel edge 11a1 and the second chisel edge 11b1 are two-fold symmetrical with respect to the rotation axis O. In other words, when the cutting part 10 is viewed from the tip part 10 a side, the first chisel edge 11 a 1 and the second chisel edge 11 b 1 are symmetric with respect to the rotation axis O of the cutting part 10. With such an arrangement, it is possible to improve the straight running stability when the work material 30 is processed.

  The two grooves 12 are mainly intended to discharge chips generated by the two cutting edges 11. Specifically, as shown in FIGS. 1 to 4, the first groove 12 a and the second groove 12 b are continuous with the first cutting edge 11 a and the second cutting edge 11 b, respectively, and the tip of the cutting portion 10. It is located in a spiral shape from the part 10a to the rear end part 10b (main body part 20 side). At the time of cutting, chips formed by the first cutting edge 11a are discharged to the rear end portion 10b side through the first groove 12a that is basically continuous to the first cutting edge 11a, and the second Chips formed by the cutting blade 11b are discharged to the rear end portion 10b side through the second groove 12b that is basically continuous with the second cutting blade 11b. In the present embodiment, the twist angle of the first groove 12a and the twist angle of the second groove 12b are the same. Further, the groove width of the first groove 12a and the groove width of the second groove 12b are the same. Further, chips formed by the first chisel edge 11a1 continuous with the one end 11aa of the first cutting edge 11a and chips formed by the second chisel edge 11b1 continuous with the one end 11ba of the second cutting edge 11b are: The sheet is discharged to the rear end portion 10b side through the first groove 12a and the second groove 12b via the fourth flank 14b2 and the second flank 14a2 positioned corresponding to the respective chisel edges 11a1 and 11b1.

The outer peripheral portion 16 (the first outer peripheral portion 16a and the second outer peripheral portion 16b) is an area in which the groove 12 is not formed as shown in FIG. 1B and FIG. The diameter) is maintained at the size before forming the groove 12. That is, the outer peripheral portion 16 is a portion substantially corresponding to the outer edge (outer periphery) 10c of the cutting portion 10 in a cross-sectional view, and has an arc shape.

  As shown in FIGS. 1B and 1C, the first outer peripheral portion 16a is continuous with the other end 11ab of the first cutting edge 11a and extends to the second groove 12b along the outer edge 10c in the front end view. ing. The first outer peripheral portion 16a has a first margin 16a1 and a first clearance 16a2. In the present specification, the front end view means that the drill 1 is viewed from the front end portion 10a side.

  As shown in FIG. 4, the first clearance 16 a 2 is continuous with the second groove 12 b and has a rotational axis O with respect to the outer edge 10 c of the cutting part 10 in the entire region along the outer edge 10 c of the cutting part 10. It is recessed at a depth D1a on the side. In the present embodiment, the first clearance 16a2 is formed from the center region of the first outer peripheral portion 16a to the second groove 12b in the front end view, and spirally from the front end portion 10a to the rear end portion 10b side region. It is formed to extend. The first clearance 16a2 has a role of reducing contact between the drill 1 and the inner wall of the processed hole 31 of the work material 30, and can contribute to improvement of chip discharge by suppressing heat generation of the drill 1.

  The first margin 16a1 is continuous with each of the other end 11ab of the first cutting edge 11a and the first clearance 16a2 when viewed from the front end, and extends spirally from the front end portion 10a to the region on the rear end portion 10b side. Is formed. In the present embodiment, as shown in FIG. 1B, the first margin 16a1 is located on the same circumference as the outer edge 10c in the front end view. According to this, at the time of drilling, the first margin 16a1 has a function of guiding the drill 1 in sliding contact with the inner wall of the processed hole 31 of the work material 30.

  As shown in FIGS. 1B and 1C, the second outer peripheral portion 16b is continuous with the other end 11bb of the second cutting blade 11b, and extends to the first groove 12a along the outer edge 10c in the front end view. ing. In the present embodiment, when viewed from the front end, the second outer peripheral portion 16b is recessed at a depth D2 on the rotation axis O side of the cutting portion 10 with respect to the outer edge 10c in the entire region along the outer edge 10c of the cutting portion 10. Yes. According to this, at the time of drilling, a gap is generated between the second outer peripheral portion 16b and the inner wall of the processed hole 31 of the work material 30, and the second outer peripheral portion 16b side of the drill 1 is supported by the inner wall of the processed hole 31. It will be in a state that is not. Thereby, the gap existing between the second outer peripheral portion 16b and the inner wall of the machining hole 31 as described above functions as a space for correcting the traveling direction of the drill 1 by the centripetal action acting on the drill 1 during drilling. As a result, the hole position accuracy can be improved. The second outer peripheral portion 16b has a first margin 16a1 and a first clearance 16a2.

  As shown in FIGS. 1B and 4, the second clearance 16b2 is continuous with the first groove 12a in the front end view, and is in the entire region along the outer edge 10c of the cutting portion 10 with respect to the outer edge 10c. It is recessed to the rotation axis O side with a depth D2a. Here, in the present embodiment, the second clearance 16b2 is formed from the center region of the second outer peripheral portion 16b to the second groove 12b in the front end view and the rear from the front end portion 10a, like the first clearance 16a2. It is formed so as to extend spirally to the region on the end 10b side. The second clearance 16b2 has a role of reducing contact between the drill 1 and the inner wall of the machining hole 31 of the work material 30, and can contribute to improvement of chip discharge by suppressing heat generation of the drill 1.

  As shown in FIGS. 1B and 4, the second margin 16 b 1 is continuous with the other end 11 bb of the second cutting edge 11 b and the second clearance 16 b 2 in the front end view, and the outer edge of the cutting portion 10. In the entire region along 10c, the outer edge 10c is recessed with a depth D2b on the rotation axis O side. That is, in the present embodiment, unlike the first margin 16a1, the second margin 16b1 is not located on the same circumference as the outer edge 10c. Further, as shown in FIGS. 1B and 4, the depth D2b is constant in the front end view. Here, the relationship between the depth D2b of the second margin 16b1 and the outer edge (outer diameter) of the cutting part 10 is 0.02 ≦ D2b / L ≦ 0. It is preferable to set in the range of 2. If it is 0.02 or more, the hole position accuracy can be improved, and if it is 0.2 or less, it is possible to minimize the positional deviation that occurs when biting the work material. The length of the second margin 16b1 in the direction of the rotation axis O is preferably longer than the diameter of the cutting part 10. According to this, since it is possible to secure a long section in which the traveling direction can be corrected by the centripetal action on the drill 1, it is possible to improve the hole position accuracy.

  Further, as shown in FIGS. 2 and 3, the second margin 16b1 extends in a spiral shape from the front end portion 10a toward the rear end portion 10b. In the present embodiment, as shown in FIG. 2, the second margin 16b1 has a terminal portion 16b11 in which the depth D2b is eliminated between the front end portion 10a and the rear end portion 10b. In other words, the second margin 16b1 ends at the end portion 16b11 which is a predetermined position of the cutting portion 10, and is located on the same circumference as the outer edge 10c of the cutting portion 10. In the present embodiment, as shown in FIGS. 2A and 6A, the second margin 16b1 has a depth D2b that decreases in the terminal portion 16b11 toward the rear end portion 10b.

  As shown in FIG. 2, the third cutting edge 11c is formed at the intersection of the terminal end 16b11 of the second margin 16b1 and the second groove 12b adjacent to the terminal end 16b11. According to this, for example, burrs or the like remaining on the inner wall of the processed hole 31 after the drilling by the first cutting edge 11a and the second cutting edge 11b located at the tip portion 10a can be effectively removed, The smoothness of the inner wall of the processed hole 31 can be improved.

  The outline 16b12 of the terminal end portion 16b11 of the second margin 16b1 is inclined with respect to the vertical line of the rotation axis O as viewed from the side, as shown in FIGS. Here, as shown in FIGS. 2B and 6B, the contour line 16b12 is a second margin 16b1 and a second outer peripheral portion 16b (corresponding to the outer edge 10c) continuous on the rear end portion 10b side. Means the boundary line. In the present embodiment, the contour line 16b12 of the end portion 16b11 of the second margin 16b1 has a positive clearance angle with respect to the vertical line of the rotation axis O, as shown in FIG. According to this, it becomes possible to reduce resistance at the time of drilling by the third cutting edge 11c. The clearance angle is preferably set in the range of 2 degrees to 15 degrees, for example. If it is 2 degrees or more, the resistance at the time of drilling can be sufficiently reduced, and if it is 15 degrees or less, the strength of the third cutting edge 11c can be sufficiently secured, so that the smoothness of the inner wall of the processed hole 31 is improved. It becomes possible to improve.

  As shown in FIG. 4, the depth D2b of the second margin 16b1 is smaller than the depth D2a of the second clearance 16b2.

  In addition, the drill 1 of this embodiment is used suitably, for example as a small diameter drill and a deep hole processing drill whose outer diameter of the cutting blade 11 is less than 0.6 mm, preferably less than 0.3 mm. In particular, it is suitable for drilling a printed circuit board or the like. Further, the drill 1 of the present embodiment is made of ultra-fine particle carbide, for example, the length of the axis (the length from the cutting edge 11 to the end of the groove 12) is L, and the diameter (outside of the cutting edge 11). When the diameter is D, it is suitably used for deep hole machining where L / D is 5 or more.

(Modification)
Below, the modification of the drill 1 which concerns on embodiment of this invention mentioned above is demonstrated. In addition, the same code | symbol may be attached | subjected to the same component and description may be abbreviate | omitted. Moreover, since the basic structure is the same as the drill 1 which concerns on the above-mentioned embodiment, the difference with the drill 1 which concerns on embodiment is mainly demonstrated, and description is abbreviate | omitted about the overlapping content. In addition, you may mutually combine the structure of each modification demonstrated below suitably.

(Modification of the second margin)
First, a first modification of the second margin 16b1 in the drill 1 according to the embodiment of the present invention will be described in detail with reference to FIG.

  In the present modification, the second margin 16b1 has a portion where the depth D2b increases as the distance from the other end 11bb of the second cutting edge 11b increases in the front end view. According to this, the depth D2b of the second margin 16b1 can be set large while ensuring the length of the second cutting edge 11b. As a result, it is possible to ensure the cutting balance between the first cutting edge 11a and the second cutting edge 11b, and at the same time, ensure a sufficient gap between the second outer peripheral portion 16 and the inner wall of the machining hole 31. The hole position accuracy can be improved by correcting the traveling direction of the drill 1.

  Next, a second modification of the second margin 16b1 in the drill 1 according to the embodiment of the present invention will be described in detail with reference to FIG.

  In the present modification, the second margin 16b1 has a portion in which the depth D2b decreases as the distance from the other end 11bb of the second cutting edge 11b increases in the front end view. According to this, since the gap existing between the second outer peripheral portion 16b and the inner wall of the machining hole 31 is gradually reduced, for example, the behavior of the drill that occurs when the work material 30 contacts the third cutting edge 11c. Changes can be reduced. As a result, it is possible to improve the smoothness of the wall surface of the processed hole and improve the hole position accuracy.

  Next, a third modification of the second margin 16b1 in the drill 1 according to the embodiment of the present invention will be described in detail with reference to FIG.

  In this modification, the depth D2b of the second margin 16b1 is substantially the same as the depth D2a of the second clearance 16b2. According to this, since the force such as runout caused by the correction of the traveling direction of the drill at the time of drilling can be received in the entire region of the second outer peripheral portion 16b, the behavior change of the drill can be reduced. As a result, it is possible to improve the smoothness of the wall surface of the processed hole and improve the hole position accuracy.

  Next, a fourth modification of the second margin 16b1 in the drill 1 according to the embodiment of the present invention will be described in detail with reference to FIG.

  In the present modification, a configuration 16a3 such as the depth D2b of the second margin 16b1 is also provided in a part of the first outer peripheral portion 16a, and the end portion located on the rear end portion 10b side of the configuration 16a3 is provided at the end portion. You may provide the 4th cutting blade 11d which has the structure similar to the 3rd cutting blade 11c. According to this, since there exists a gap between the inner wall of the processing hole 31 for each of the first outer peripheral portion 16a and the second outer peripheral portion 16b during drilling, the centripetal that acts on the drill 1 during drilling processing. The space for correcting the traveling direction of the drill 1 can be functioned more effectively by the action, and as a result, the hole position accuracy can be further improved, and the inner wall of the machining hole 31 can be formed by the fourth cutting edge 11d. It is possible to effectively remove burrs and the like remaining on the surface, and to improve the smoothness of the inner wall of the processed hole 31.

(Modification of the third cutting edge)
Next, the modification of the 3rd cutting blade 11c among the drills 1 which concern on embodiment of this invention is demonstrated in detail with reference to Fig.9 (a).

  In the present modification, the third cutting edge 11c is linear. According to this, since the force applied to the third cutting edge 11c during processing is evenly distributed, it is possible to reduce the deficiency of the third cutting edge 11c and to improve the smoothness of the wall surface of the processing hole. This can be further improved.

(Modification of the end portion of the second margin)
Next, a second modification of the end portion 16b11 of the second margin 16b1 in the drill 1 according to the embodiment of the present invention will be described in detail with reference to FIG. 9B.

  In the present modification, the outline 16b12 of the end portion 16b11 of the second margin 16b1 has a negative clearance angle with respect to the normal of the rotation axis O. According to this, in addition to the 3rd cutting blade 11c or instead of the 3rd cutting blade 11c, it becomes possible for the outline 16b12 to function as a cutting blade. As a result, burrs and the like remaining on the inner wall of the processing hole 31 after the drilling by the first cutting edge 11a and the second cutting edge 11b positioned at the tip portion 10a can be effectively removed, and the inner wall of the processing hole 31 It is possible to improve the smoothness.

<Manufacturing method of cut product>
Next, the manufacturing method of the cut workpiece which concerns on embodiment of this invention is demonstrated in detail, giving the case where the drill 1 which concerns on the above-mentioned embodiment is used as an example. Hereinafter, a description will be given with reference to FIG.

  The manufacturing method of the cut workpiece according to the present embodiment includes the following steps (i) to (iv).

(I) The process of arrange | positioning the drill 1 upwards with respect to the prepared work material 30 (refer Fig.10 (a)).

  (Ii) The step of rotating the drill 1 around the rotation axis O in the direction of arrow a to bring the drill 1 closer to the work material 30 (see FIGS. 10A and 10B).

  This step can be performed, for example, by fixing the work material 30 on a table of a machine tool to which the drill 1 is attached and bringing the drill 1 closer in a rotated state. In this step, the work material 30 and the drill 1 may be relatively close to each other. For example, the work material 30 may be close to the drill 1.

(Iii) The drill 1 rotating by bringing the drill 1 closer to the work material 30
The first cutting blade 11a and the second cutting blade 11b are brought into contact with desired positions on the surface of the work material 30 to form a machining hole (through hole) 31 in the work material 30 (FIG. 10B). )reference).

  In this step, from the viewpoint of obtaining a good finished surface, it is preferable to set so that a part of the cutting portion 10 of the drill 1 on the rear end portion 10 b side does not penetrate the work material 30. That is, by making this partial region function as a margin region for chip discharge, it is possible to achieve excellent chip discharge properties through the region.

  (Iv) A step of separating the drill 1 from the work material 30 (see FIG. 10C).

  Also in this step, similarly to the above-described step (ii), the work material 30 and the drill 1 may be relatively separated from each other. For example, the work material 30 may be separated from the drill 1.

  By going through the steps as described above, excellent hole workability can be exhibited.

  In addition, when performing the cutting process of the workpiece 30 as described above a plurality of times, for example, when forming a plurality of processed holes (through holes) 31 on one workpiece 30, the drill 1 What is necessary is just to repeat the process which makes the 1st cutting edge 11a and the 2nd cutting edge 11b of the drill 1 contact the different location of the cut material 30, hold | maintaining the state which rotated.

  As mentioned above, although some embodiment and modification which concern on this invention were illustrated, this invention is not limited to these, It cannot be overemphasized that it is arbitrary, unless it deviates from the summary of this invention. .

  For example, the shape of the cutting part 10 is not limited to the structure of the above-mentioned embodiment, The shape normally used by those skilled in the art can be adopted. For example, the cutting part 10 may be tapered so that the core thickness of the inscribed circle increases from the front end part 10a toward the rear end part 10b. Moreover, the cutting part 10 may be inclined so that the drill diameter (outer diameter) becomes larger or smaller as it goes from the front end part 10a to the rear end part 10b. Further, the cutting part 10 may be provided with an undercut part.

  In the above-described embodiment, the groove widths of the first groove 12a and the second groove 12b are the same, but instead, the one of the first groove 12a and the second groove 12b that is located on the tip portion 10a side. The groove width may be increased. According to this, it becomes possible to discharge | emit effectively about the comparatively big chip through the groove | channel 12 by the side of the front-end | tip part 10a. Further, the distance may increase or decrease from the front end portion 10a toward the rear end portion 10b.

  Moreover, the groove length of the 1st groove | channel 12a and the 2nd groove | channel 12b may differ. Furthermore, the two grooves may be joined by changing the twist angle of one or both of the first groove 12a and the second groove 12b.

DESCRIPTION OF SYMBOLS 1 Drill 10 Cutting part 10a Front end part 10b Rear end part 10c Outer edge 11 Cutting edge 11a 1st cutting edge 11aa One end 11ab Other end 11b 2nd cutting edge 11ba One end 11bb Other end 11a1 1st chisel edge 11b1 2nd chisel edge 11c 3rd cutting edge 11d Fourth cutting edge 12 Groove 12a First groove 12b Second groove 14 Flank 14a1 First flank 14a2 Second flank 14b1 Third flank 14b2 Fourth flank 16 Outer part 16a First outer part 16a1 First margin 16a2 First clearance 16b Second outer peripheral portion 16b1 Second margin 16b11 End portion 16b12 Contour line 16b2 Second clearance 20 Main body portion 30 Work material 31 Processing hole (through hole)
O Rotating shaft

Claims (20)

A first chisel edge and a second chisel edge, which are continuously located at the tip,
A first cutting edge having one end continuous to the first chisel edge;
A second cutting edge having one end continuous to the second chisel edge;
A first groove that is continuous with the first cutting edge and extends spirally toward the rear end;
A second groove that is continuous with the second cutting edge and extends spirally toward the rear end;
A first outer peripheral portion that is continuous with the other end of the first cutting edge and extends to the second groove along the outer edge in a front end view;
A cylindrical cutting part that is continuous with the other end of the second cutting edge and has a second outer peripheral part extending to the first groove along the outer edge in a front end view;
In the front end view, the second outer peripheral portion is recessed at a depth D2 on the rotation axis side of the cutting portion with respect to the outer edge in the entire region along the outer edge of the cutting portion.   The first outer peripheral portion is continuous with the second groove in a front end view and has a depth D1a on the rotating shaft side with respect to the outer edge of the cutting portion in the entire region along the outer edge of the cutting portion. The drill according to claim 1, having a recessed first clearance.   3. The drill according to claim 2, wherein the first outer peripheral portion further has a first margin continuous to each of the other end of the first cutting edge and the first clearance in a front end view.   The length of the said 1st cutting blade is a drill in any one of Claims 1-3 longer than the length of the said 2nd cutting blade.   The drill according to any one of claims 1 to 4, wherein the first chisel edge and the second chisel edge are symmetrical with respect to the rotation axis.   The second outer peripheral portion is continuous with the first groove in a front end view and is recessed at a depth D2a toward the rotation axis with respect to the outer edge in the entire region along the outer edge of the cutting portion. The drill according to any one of claims 1 to 5, which has two clearances.   The drill according to claim 6, wherein the second clearance is continuous with the other end of the second cutting edge in a front end view.   The drill according to claim 6 or 7, wherein a length of the second margin in a direction of the rotation axis is longer than a diameter of the cutting portion.   The second outer peripheral portion is continuous with the other end of the second cutting edge and the second clearance in the front end view, and is in the entire region along the outer edge of the cutting portion with respect to the outer edge. The drill according to any one of claims 6 to 8, further comprising a second margin recessed at a depth D2b on the rotating shaft side.   The drill according to claim 9, wherein the second margin has a portion where the depth D2b decreases as the distance from the other end of the second cutting edge increases in a front end view.   The drill according to claim 9 or 10, wherein the second margin has a portion where the depth D2b increases as the distance from the other end of the second cutting edge increases in a front end view.   The drill according to any one of claims 9 to 11, wherein the depth D2b of the second margin is smaller than the depth D2a of the second clearance.   The drill according to any one of claims 9 to 12, wherein the second margin extends spirally toward the rear end portion.   The drill according to claim 13, wherein the second margin has a terminal portion where the depth D2b disappears between the tip portion and the rear end portion.   The drill according to claim 14, wherein the depth D2b of the second margin decreases toward the rear end at the terminal end.   The drill according to claim 14 or 15, further comprising a third cutting edge positioned at a line of intersection between the terminal end of the second margin and the second groove adjacent to the terminal end.   The drill according to any one of claims 14 to 16, wherein, in a side view, an outline of the end portion of the second margin is inclined with respect to a normal of the rotation axis.   18. The drill according to claim 17, wherein, in a side view, a contour line of the end portion of the second margin has a positive clearance angle with respect to a perpendicular to the rotation axis.   The drill according to any one of claims 14 to 18, wherein a contour line of the end portion of the second margin is curved. Rotating the drill according to any one of claims 1 to 19 around a rotation axis;
Contacting the work piece with the first cutting edge and the second cutting edge of the rotating drill;
Separating the work material and the drill;
A method for manufacturing a cut product.

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