Micro Drill

Abstract

The objective of the present invention is to provide a micro drill. [Solution] A microdrill with a tip portion, the tip portion having two stages of short chisel edges arranged symmetrically with respect to the center, at least one stage of first cutting edge having a slope different from that of the short chisel edges at ends separated from each other, and when multiple stages of the first cutting edges are provided, the slopes between the multiple stages of the first cutting edges are different. This microdrill changes the chisel edge of a conventional drill to a short chisel edge with a different slope and at least one stage of first cutting edge, thereby shortening the length of the conventional chisel edge, improving the centering ability of the hole drilling, and thickening the core thickness of the microdrill via the first cutting edge, thereby improving the centering effect of the microdrill and increasing the strength of the microdrill.

Description

[Technical Field]

[0001] The present invention relates to the field of drills, and in particular to micro drills. [Background technology]

[0002] Drills with a diameter less than 3.175 mm are commonly referred to as microdrills. In the development and design of micro drills, the material, tip structure, tip, core thickness, etc. are all parameters that can have a significant impact on the performance of the micro drill. For example, take a diamond microdrill. The diameter of a diamond microdrill is basically less than 1 mm. If the core thickness is large, the centering effect is poor, and if the core thickness is small, the drill strength is reduced and it becomes more likely to break. Although diamond is extremely hard, it has poor toughness and is prone to chipping when a large cutting force is applied. Therefore, it was necessary to improve the structure of the tip portion to reduce the chipping problem. Summary of the Invention [Problem to be solved by the invention]

[0003] The object of the present invention is to provide a microdrill that changes the chisel edge of a conventional drill to a short chisel edge with a different slope and a first cutting edge with at least one stage, thereby shortening the length of the conventional chisel edge, improving the centering ability of drilling, and increasing the core thickness of the microdrill via the first cutting edge, thereby improving the centering effect of the microdrill and increasing the strength of the microdrill. [Means for solving the problem]

[0004] In order to achieve the above object, the present invention employs the following technical means.

[0005] The present invention relates to a microdrill having a tip portion, wherein the tip portion has two stages of short chisel edges arranged symmetrically with respect to the center, and at least one stage of first cutting edge is provided at ends of the short chisel edges that are spaced apart from each other, the slope of which differs from that of the short chisel edges, and when multiple stages of the first cutting edges are provided, the slopes of the multiple stages of the first cutting edges are different, In other words, it is a microdrill having a tip portion, the tip portion having a chisel edge, the chisel edge being divided into two short chisel edges extending symmetrically from the center of the tip portion and having a predetermined slope, and two first cutting edges extending symmetrically from the end of each short chisel edge with respect to the center and having a slope different from that of the corresponding short chisel edge, each short chisel edge being shorter than the chisel edge, and when each first cutting edge is composed of a plurality of short cutting edges shorter than the first cutting edges, the slopes of the short cutting edges of these first cutting edges are different, and the slope is a slope with respect to a plane perpendicular to the central axis of the tip portion, and the short chisel edges are shorter than the length of conventional chisel edges, thereby improving the centering effect of drilling while increasing the core thickness via the first cutting edges and increasing the strength of the microdrill.

[0006] Furthermore, the included angle between the two short chisel edges is 140 to 170 degrees, In other words, the angle formed between one of the two short chisel edges and the other short chisel edge is 140° to 170°, and if the included angle is too large, the sharpness of the tip will decrease, and if the included angle is too small, the strength of the tip will decrease, making it prone to chipping, breakage, and other phenomena.

[0007] Furthermore, the included angle between the corresponding two first cutting edges is 140 to 170 °, and the included angle between the two first cutting edges is smaller than or equal to the included angle between the two short chisel edges; In other words, the angle between one of the two first cutting edges and the other first cutting edge is 140° to 170°, and the angle between these two first cutting edges is smaller than or equal to the angle between the two short chisel edges.If the included angle is too large, the sharpness of the tip will decrease, and if the included angle is too small, the strength of the tip will decrease, easily causing phenomena such as chipping and breakage.

[0008] Furthermore, an edge portion corresponding to the one-stage or multi-stage first cutting edge is a first edge portion, and the one-stage first cutting edge corresponds to one of the first edge portions, and the multi-stage first cutting edge corresponds to a plurality of the first edge portions on different planes, and an edge intersecting with the spiral flute in the first edge portion forms a second cutting edge, In other words, the edge portions corresponding to the two first cutting edges are each first edge portions, and when each first cutting edge is composed of a plurality of short cutting edges, each short first cutting edge corresponds to a plurality of first sub-edge portions on different planes, and the plurality of first sub-edge portions constitute the first edge portion, and the edges that intersect with the helical grooves in each first edge portion each form a second cutting edge, and by lengthening the length of the edge line via the second cutting edge, the external force received is locally reduced and the problem of chipping and chipping of the cutting edge is improved.

[0009] Furthermore, the range of the included angle between the first edge portion and the spiral groove is 50 to 70 degrees, In other words, the angle between each first edge portion and the helical groove is 50° to 70°, and if the included angle is too large, the sharpness of the tip will decrease, and if the included angle is too small, the strength of the tip will decrease, making it prone to chipping, breakage, and other phenomena.

[0010] Furthermore, the included angle between the corresponding two second cutting edges is 90 to 150 °, and the spatial included angle between the two second cutting edges is smaller than or equal to the included angle between the two first cutting edges; In other words, the angle between one of the two second cutting edges and the other second cutting edge is 90° to 150°, and the angle between these two second cutting edges is smaller than or equal to the angle between the two first cutting edges.If the included angle is too large, the sharpness of the tip will decrease, and if the included angle is too small, the strength of the tip will decrease, easily causing phenomena such as chipping and breakage.

[0011] Furthermore, at least one third cutting edge having a slope different from that of the second cutting edge is provided at ends spaced apart from each other of the second cutting edge, and when multiple third cutting edges are provided, the slopes between the multiple third cutting edges are different, In other words, when each second cutting edge end is provided with two third cutting edges that extend symmetrically from this end relative to the center and have a different slope from the corresponding second cutting edge, and each third cutting edge is composed of a plurality of short cutting edges that are shorter than this third cutting edge, the slopes of the short cutting edges in this third cutting edge are different, and the conventional one-piece cutting edge is replaced with a multi-stage cutting edge, which on the one hand further increases the length of the edge line, reduces the external force received locally, and improves the problem of chipping and breaking of the cutting edge, and on the other hand, the cutting amount and cutting pressure of each cutting edge can be adjusted based on the design of the length and angle of each cutting edge, and further improves the problem of chipping and breaking of the cutting edge.

[0012] Furthermore, the spatial included angle between the corresponding two third cutting edges is 50 to 150 °, and the spatial included angle between the two third cutting edges is smaller than or equal to the spatial included angle between the two second cutting edges; In other words, the angle between one of the two third cutting edges and the other third cutting edge is 50° to 150°, and the angle between these two third cutting edges is smaller than or equal to the angle between the two second cutting edges.If the air angle is too large, the sharpness of the tip will decrease, and if the air angle is too small, the strength of the tip will decrease, easily causing phenomena such as chipping and breakage.

[0013] Furthermore, a third edge portion intersects with the spiral flute to form the third cutting edge, and an included angle between the third edge portion and the spiral flute is 30 to 60 degrees, In other words, the edge portion that intersects with the spiral groove to form the third cutting edge is the third edge portion, and the angle between the third edge portion and the spiral groove is 30° to 60°.If the included angle is too large, the sharpness of the tip will decrease, and if the included angle is too small, the strength of the tip will decrease, easily causing phenomena such as chipping and breakage.

[0014] Furthermore, a second edge portion intersects with the first edge portion to form the first cutting edge, and an angle between the first edge portion and the second edge portion is 90 to 130 degrees, In other words, the edge portion that intersects with the first edge portion to form the first cutting edge is the second edge portion, and the angle formed by the first edge portion and the second edge portion is 90° to 130°. If the included angle is too large, the sharpness of the tip will decrease, and if the included angle is too small, the strength of the tip will decrease, easily causing phenomena such as chipping and breakage. [Effects of the Invention]

[0015] On the other hand, the length of the conventional chisel edge is shortened to improve the centering ability of drilling, and at the same time, the core thickness of the micro drill is increased through the single-stage or multi-stage first cutting edge. This solves the contradiction of the conventional drill that when the core thickness is large, the centering is poor and when the core thickness is small, the strength is low, and improves the centering effect of the micro drill while increasing the strength of the micro drill. On the other hand, by replacing the conventional one-piece cutting edge with a multi-stage cutting edge (comprising a first cutting edge, a second cutting edge and a third cutting edge), the length of the edge line can be further increased, the external force locally reduced, and the chipping and breakage of the cutting edge can be improved. In addition, the cutting amount and cutting pressure of each cutting edge can be adjusted based on the length and angle design of each cutting edge, which can further improve the chipping and breakage of the cutting edge. [Brief explanation of the drawings]

[0016] [Figure 1] 1 is a schematic diagram showing an outline of the three-dimensional structure of a tip portion of a microdrill according to an embodiment of the present invention. [Figure 2] 3 is a schematic diagram showing an edge portion on an end surface of a tip portion according to an embodiment of the present invention. FIG. [Figure 3] 3 is a schematic diagram showing cutting edges corresponding to the edge portion arrangement of FIG. 2. [Figure 4] FIG. 1 is a schematic diagram illustrating the included angle θ1 of two short chisel edges according to an embodiment of the present invention. [Figure 5] 4 is a schematic view showing an included angle θ2 between two first cutting edges according to one embodiment of the present invention. FIG. [Figure 6] 10 is a schematic diagram showing an included angle θ3 between two second cutting edges according to an embodiment of the present invention. FIG. [Figure 7] 10 is a schematic diagram showing an included angle θ4 between two third cutting edges according to an embodiment of the present invention. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0017] In the description of the present invention, terms indicating orientations or positional relationships are orientations or positional relationships shown based on the drawings, and are merely used to facilitate easy description of the present invention. They do not necessarily indicate or suggest that the devices or components shown have a specific orientation or are configured and operated in a specific orientation, and therefore should not be understood as limitations on the present invention.

[0018] The principles and features of the present invention will now be described with reference to the accompanying drawings, in which the examples given are used only to illustrate the present invention and are not intended to limit the scope of the present invention. It should be noted that the drawings are in very simplified form and to an untrue scale and are used solely for the purpose of assisting in easily and clearly describing embodiments of the present invention.

[0019] As shown in FIG. 1, in one embodiment of the present invention, a microdrill includes a tip portion and a spiral flute provided on the outer periphery of the drill. The tip portion has two stages of short chisel edges 3 arranged symmetrically with respect to the center, and at least one stage of first cutting edge 4 (the said stage of first cutting edge 4 can be understood as the inclination or slope, and directly affects the magnitude of the included angle; the same applies hereinafter) is provided at the ends of the short chisel edges 3 that are apart from each other and has a different gradient from that of the short chisel edges 3. When a multi-stage first cutting edge 4 is provided, the gradients between the multi-stage first cutting edges are different, and an edge portion corresponding to one or more stage first cutting edges 4 is a first edge portion, and one stage of first cutting edge 4 corresponds to one first edge portion, and the multi-stage first cutting edge 4 is composed of a plurality of first edge portions (multi-stage first cutting edges) on different planes. Since the inclinations of the cutting edges 4 are different, the first edge portions corresponding to the multi-stage first chip cutting edges 4 are on different planes, and the fourth edge portion intersects with the first edge portion to form a short chisel edge, the second edge portion intersects with the first edge portion to form the first cutting edge, and the edges intersecting with the spiral flutes 7 within the first edge portion form the second cutting edges 5, and at least one third cutting edge 6 having a different inclination from the second cutting edges 5 is provided at the ends spaced apart from each other, and when multi-stage third cutting edges 6 are provided, the inclinations between the multi-stage third cutting edges 6 are different, and it is the third edge portion that intersects with the spiral flute to form the third cutting edge.

[0020] In this embodiment, for simplicity of explanation, the first cutting edge 4 and the third cutting edge 6 each have only one stage, and taking the installation of a diamond microdrill as an example, the tip portion has cutting sets that are symmetrical about the center, and two spiral grooves 7 are drilled in the two corresponding cutting sets.

[0021] As shown in Figure 2, each cutting set has a first edge portion, a second edge portion, a third edge portion, and a fourth edge portion. To easily distinguish between the edge portions on the two cutting sets, the edge portions on one cutting set are referred to as the first edge portion a11, the second edge portion a12, the third edge portion a13, and the fourth edge portion a14, respectively, and the edge portions corresponding to the above edge portions on the other cutting set are referred to as the first edge portion b21, the second edge portion b22, the third edge portion b23, and the fourth edge portion b24, respectively.

[0022] As shown in Figures 2 and 3, the intersections between the first edge portion of one set and the fourth edge portion of the other set are the intersecting edge between the first edge portion a11 and the fourth edge portion b24 and the intersecting edge between the first edge portion b21 and the fourth edge portion a14, and these two intersecting edges are short chisel edges 3, and as shown in Figure 4, the included angle θ1 between the two short chisel edges 3 is 140 to 170°. 2 and 3, the intersections between the first edge portions of one set and the second edge portions of the other set are the intersection edges of the first edge portion a11 and the second edge portion b22 and the intersection edges of the first edge portion b21 and the second edge portion a12. These two intersection edges are the first cutting edges 4, and the slopes of the first cutting edges 4 and the short chisel edge 3 are different. As shown in FIG. 5, the included angle θ2 between the two first cutting edges 4 is 140 to 170°, and the included angle between the first edge portion and the second edge portion is 0 to 130°. More specifically, the included angle between the first edge portion a11 and the second edge portion b22 and the included angle between the first edge portion b21 and the second edge portion a12 are 90 to 130°. Continuing to show in Figures 2 and 3, the intersection edge between the first edge portion a11 and the helical groove 7 and the intersection edge between the first edge portion b21 and the helical groove 7 are the second cutting edges 5, and as shown in Figure 6, the spatial included angle θ3 between the two second cutting edges 5 is 90 to 150°, and the spatial included angle is the angle formed by projecting the two cutting edges onto the same plane (the same applies below), and the included angle range between the first edge portion and the helical groove 7 is 50 to 70°, and more specifically, the included angle range between the first edge portion a11 and the helical groove 7 and the included angle range between the first edge portion b21 and the helical groove 7 are 50 to 70°. Continuing to show in Figures 2 and 3, the intersection edge between the third edge portion a13 and the helical groove 7 and the intersection edge between the third edge portion b23 and the helical groove 7 are the third cutting edges 6, and as shown in Figure 7, the spatial angle θ4 between the two third cutting edges 6 is 50 to 150°, and the angle between the third edge portion and the helical groove is 30 to 60°.More specifically, the angle between the third edge portion a13 and the helical groove 7 and the angle between the third edge portion b23 and the helical groove 7 are 30 to 60°.

[0023] By shortening the length of the chisel edge, the centering ability of the drilling is improved, and by increasing the core thickness of the micro-drill via the first cutting edge 4, the centering effect of the micro-drill can be improved while increasing the strength of the micro-drill. The multi-stage cutting edge replaces the conventional one-piece cutting edge, on the one hand, increasing the length of the edge line and reducing the external force locally received, thereby improving the problem of chipping and breaking of the cutting edge, and on the other hand, the cutting amount and cutting pressure of each cutting edge can be adjusted based on the design of the length and angle of each cutting edge. For example, if the chipping problem at the third cutting edge 6 is significant, the cutting amount of the third cutting edge 6 can be reduced by extending the length of the second cutting edge 5, or the cutting pressure of the third cutting edge 6 can be reduced by reducing the spatial angle between the two third cutting edges 6. Both of these adjustment methods can improve the chipping problem at the third cutting edge 6.

[0024] It should be noted that this specification is explained based on embodiments, but each embodiment does not include only one independent technical means, and the description method of the specification is intended to clearly explain the technical content of the present invention. Those skilled in the art can view the specification as a whole and appropriately combine the technical means in each embodiment to form other embodiments that can be understood by those skilled in the art. [Explanation of symbols]

[0025] 11 First edge portion a 12 Second edge portion a 13 Third edge portion a 14 Fourth edge portion a 21 First edge portion b 22 Second edge portion b 23 Third edge part b 24 Fourth edge b 3. Short chisel edge 4 First cutting edge 5 Second cutting edge 6 Third cutting edge 7. Helical groove

Claims

1. A micro drill having a tip portion, The tip portion has a chisel edge, The chisel edge is divided into two short chisel edges extending symmetrically from the center of the tip portion and having a predetermined inclination, and two first cutting edges extending symmetrically from the ends of each short chisel edge with respect to the center and having an inclination different from that of the corresponding short chisel edge, In the first case where each first cutting edge is constituted only by this first cutting edge, the inclinations of the two first cutting edges are the same; In a second case where each first cutting edge is configured by a plurality of short cutting edges that are shorter than the first cutting edge, the inclinations of the short cutting edges in the first cutting edge are different, The microdrill, wherein the gradient is a gradient with respect to a plane perpendicular to the central axis of the tip portion.

2. 2. The microdrill according to claim 1, wherein an angle formed between one of the two short chisel edges and the other short chisel edge is between 140° and 170°.

3. 2. The micro drill according to claim 1, wherein in the first case, an angle formed between one of the two first cutting edges and the other first cutting edge is 140° to 170°, and the angle formed between the two first cutting edges is smaller than an angle formed between the two short chisel edges.

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