A micro drill bit

Abstract

A micro drill bit comprises a drill tip, the drill tip comprises two short chisels arranged symmetrically in the center, at least one first cutting edge with gradient different from the short chisel is arranged at the end of the short chisel away from each other, and the short chisel is provided with multiple first cutting edges, and the gradients between the multiple first cutting edges are different. The micro drill bit changes the chisel of the traditional drill bit into the short chisel with different gradients and at least one first cutting edge, so as to reduce the length of the traditional chisel, improve the drilling centering ability, increase the core thickness of the micro drill by the first cutting edge, enhance the strength of the micro drill while improving the centering effect of the micro drill.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of drill bits, in particular to a micro drill bit. BACKGROUND

[0002] Drill bits with a diameter less than 3.175mm, commonly known as micro drill bits, are referred to as micro drills. In the development and design of micro drills, material, front end structure, drill tip, core thickness and other parameters can have a significant impact on the performance of the micro drill. For example, a diamond micro drill has a diameter of less than 1mm, and has a large core thickness, poor centering effect, small core thickness, reduced drill bit strength, and is prone to breakage. In addition, although diamond has high hardness, its toughness is poor, and the cutting force is large, the blade edge is prone to collapse. Therefore, the structure of the drill tip of the drill bit needs to be improved to reduce the problem of blade collapse. SUMMARY

[0003] The purpose of the present application is to provide a micro drill bit, which changes the traditional chisel edge to a short chisel edge with different gradients and at least one first cutting edge, to reduce the length of the traditional chisel edge, improve the centering ability of drilling, and increase the core thickness of the micro drill by the first cutting edge, thereby improving the centering effect of the micro drill and enhancing the strength of the micro drill.

[0004] To achieve the above-mentioned purpose, the present application adopts the following technical solutions:

[0005] A micro drill bit, comprising a drill tip, the drill tip comprising two short chisel edges arranged symmetrically about the center, at least one first cutting edge with different gradients than the short chisel edges being arranged at the ends of the short chisel edges away from each other, and a plurality of first cutting edges being arranged, the gradients between the plurality of first cutting edges being different; the length of the short chisel edge is smaller than that of the traditional chisel edge, thereby improving the centering effect of drilling, and the core thickness is increased by the first cutting edge, thereby enhancing the strength of the micro drill;

[0006] Correspondingly, the included angle between the two short chisel edges is 140-170°; if the included angle is too large, the drill tip will be less sharp, and if the included angle is too small, the drill tip will be low in strength and prone to collapse, marking and other phenomena;

[0007] Correspondingly, the included angle between the two first cutting edges is 140-170°, and the included angle between the two first cutting edges is less than or equal to the included angle between the two short chisel edges; if the included angle is too large, the drill tip will be less sharp, and if the included angle is too small, the drill tip will be low in strength and prone to collapse, marking and other phenomena;

[0008] Correspondingly, the cutting surface corresponding to one or more of the first cutting edges is a first edge surface, one of the first cutting edges corresponds to one of the first edge surfaces, and multiple first cutting edges correspond to multiple first edge surfaces in different planes, and the intersection of the first edge surface and the helical chip groove forms a second cutting edge; the second cutting edge increases the length of the edge line, reduces the local stress, and improves the problem of edge cracking;

[0009] Correspondingly, the included angle between the first edge surface and the helical chip groove is 50-70°; an excessively large included angle will result in poor sharpness of the drill tip, and an excessively small included angle will result in low strength of the drill tip, which is prone to cracking and marking;

[0010] Correspondingly, the included angle between the first edge surface and the helical chip groove is 50-70°; an excessively large included angle will result in poor sharpness of the drill tip, and an excessively small included angle will result in low strength of the drill tip, which is prone to cracking and marking;

[0011] Correspondingly, the included angle between the first edge surface and the helical chip groove is 50-70°; an excessively large included angle will result in poor sharpness of the drill tip, and an excessively small included angle will result in low strength of the drill tip, which is prone to cracking and marking;

[0012] Correspondingly, the included angle between the first edge surface and the helical chip groove is 50-70°; an excessively large included angle will result in poor sharpness of the drill tip, and an excessively small included angle will result in low strength of the drill tip, which is prone to cracking and marking;

[0013] Correspondingly, the included angle between the first edge surface and the helical chip groove is 50-70°; an excessively large included angle will result in poor sharpness of the drill tip, and an excessively small included angle will result in low strength of the drill tip, which is prone to cracking and marking;

[0014] Correspondingly, the included angle between the first edge surface and the helical chip groove is 50-70°; an excessively large included angle will result in poor sharpness of the drill tip, and an excessively small included angle will result in low strength of the drill tip, which is prone to cracking and marking.

[0015] The beneficial effects of the present application are:

[0016] On the one hand, the length of the traditional chisel edge is reduced to improve the drilling centering capability, and the first cutting edge or the first cutting edges are used to increase the core thickness of the micro drill, thereby coordinating the contradiction between the large core thickness and the poor centering of the traditional drill bit, the small core thickness and the low strength, improving the centering effect of the micro drill, and enhancing the strength of the micro drill;

[0017] On the other hand, the multi-segment cutting edge (including the first cutting edge, the second cutting edge and the third cutting edge) is used to replace the traditional integral cutting edge, the length of the cutting edge is increased, the local stress is reduced, the problem of edge cracking is improved, and the cutting amount and cutting pressure of each cutting edge can be adjusted according to the design of the length and angle of each cutting edge, thereby further improving the problem of edge cracking. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 is a schematic diagram of the drill tip part of the micro drill according to an embodiment of the present application;

[0019] Figure 2 is a schematic diagram of the edge surface on the end face of the drill tip part according to an embodiment of the present application;

[0020] Figure 3 is a schematic diagram of the edge surface corresponding to the edge surface distribution of Figure 2 ;

[0021] Figure 4 is a schematic diagram of the included angle θ1 of the two short chisel edges according to an embodiment of the present application;

[0022] Figure 5 is a schematic diagram of the included angle θ2 of the two first cutting edges according to an embodiment of the present application;

[0023] Figure 6 is a schematic diagram of the included angle θ3 of the two second cutting edges according to an embodiment of the present application;

[0024] Figure 7 is a schematic diagram of the included angle θ4 of the two third cutting edges according to an embodiment of the present application;

[0025] in the figure:

[0026] 11, first edge surface a; 12, second edge surface a; 13, third edge surface a; 14, fourth edge surface a;

[0027] 21, first edge surface b; 22, second edge surface b; 23, third edge surface b; 24, fourth edge surface b;

[0028] 3, short chisel edge; 4, first cutting edge; 5, second cutting edge; 6, third cutting edge; 7, spiral flute. DETAILED DESCRIPTION

[0029] In the description of this invention, it should be understood that the terms or positional relationships indicating orientation are based on the orientation or positional relationships shown in the accompanying drawings, and are only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0030] The principles and features of the present invention are described below with reference to the accompanying drawings. The examples given are for illustrative purposes only and are not intended to limit the scope of the invention. It should be noted that the drawings are all in a very simplified form and use non-precise proportions, and are only used to facilitate and clarify the illustration of the embodiments of the present invention.

[0031] like Figure 1 As shown, in one embodiment of the present invention, the micro drill bit includes a drill tip and a spiral chip removal groove disposed around the drill bit. The drill tip includes two short chisel edges 3 arranged symmetrically at the center. At least one first cutting edge 4 with a gradient different from that of the short chisel edges 3 is provided at the end of the short chisel edges 3 that is far apart from each other (the gradient can be understood as slope or inclination, which directly affects the size of the included angle, the same below). If multiple first cutting edges 4 are provided, the gradients between the multiple first cutting edges 4 are not the same. The cutting surface corresponding to one or more first cutting edges 4 is the first cutting face. One first cutting edge 4 corresponds to one first cutting face, and multiple first cutting edges 4 correspond to multiple first cutting faces on different planes (because the gradients of multiple first cutting edges 4 are different). Since the gradients are different, the first cutting edges corresponding to the multiple first cutting edges 4 will be on different planes. The first cutting edge that intersects with the first cutting edge to form a short transverse cutting edge 3 is the fourth cutting edge. The first cutting edge that intersects with the first cutting edge to form a first cutting edge is the second cutting edge. The cutting edge that intersects with the spiral chip removal groove 7 in the first cutting edge forms a second cutting edge 5. At least one third cutting edge 6 with a gradient different from the second cutting edge 5 is provided at the end of the second cutting edge 5 that is far away from each other. If there are multiple third cutting edges 6, the gradients between the multiple third cutting edges 6 are also different. The third cutting edge 6 that intersects with the spiral chip removal groove 7 to form a third cutting edge is the third cutting edge.

[0032] In this embodiment, for the sake of simplicity, both the first cutting edge 4 and the third cutting edge 6 are only provided in one section. Taking the diamond micro drill as an example, the drill tip includes two centrally symmetrical cutting groups, and two spiral chip removal grooves 7 are opened corresponding to the two cutting groups.

[0033] like Figure 2As shown in the drawings, each cutting group comprises a first land, a second land, a third land and a fourth land, in order to distinguish the lands on the two cutting groups, the lands on one cutting group are called first land a11, second land a12, third land a13 and fourth land a14 respectively, and the lands on the other cutting group are called first land b21, second land b22, third land b23 and fourth land b24 respectively.

[0034] As shown in the drawings, Figure 2 and 3 the intersection of the first land in one group and the fourth land in the other group, i.e. the intersection of first land a11 and fourth land b24 and the intersection of first land b21 and fourth land a14, are two short horizontal lands 3, as shown in the drawings, Figure 4 the included angle θ1 between the two short horizontal lands 3 is 140-170°. As shown in the drawings, Figure 2 and 3 the intersection of the first land in one group and the second land in the other group, i.e. the intersection of first land a11 and second land b22 and the intersection of first land b21 and second land a12, are two first cutting lands 4, the gradient of the first cutting lands 4 is different from that of the short horizontal lands 3, as shown in the drawings, Figure 5 the included angle θ2 between the two first cutting lands 4 is 140-170°, and the included angle between the first land and the second land is 90-130°, more specifically, the included angle between first land a11 and second land b22 and the included angle between first land b21 and second land a12 are 90-130°. As shown in the drawings, Figure 2 and 3 the intersection of first land a11 and the spiral chip flute 7 and the intersection of first land b21 and the spiral chip flute 7 are second cutting lands 5, as shown in the drawings, Figure 6 the spatial included angle θ3 between the two second cutting lands 5 is 90-150°, the spatial included angle is the included angle formed by projecting the two cutting lands onto the same plane, the same below, the included angle between the first land and the spiral chip flute is 50-70°, more specifically, the included angle between first land a11 and the spiral chip flute 7 and the included angle between first land b21 and the spiral chip flute 7 are 50-70°. As shown in the drawings, Figure 2 and 3 the intersection of third land a13 and the spiral chip flute 7 and the intersection of third land b23 and the spiral chip flute 7 are third cutting lands 6, as shown in the drawings, Figure 7 the spatial included angle θ4 between the two third cutting lands 6 is 50-150°, the included angle between the third land and the spiral chip flute is 30-60°, more specifically, the included angle between third land a13 and the spiral chip flute 7 and the included angle between third land b23 and the spiral chip flute 7 are 30-60°.

[0035] By reducing the length of the short cross blade 3, the drilling centering ability is improved, and the core thickness of the micro drill is increased by the first cutting edge 4, so that the micro drill centering effect is improved while the strength of the micro drill is enhanced. At the same time, the multi-section cutting edge replaces the traditional integral cutting edge, on the one hand, the length of the blade line is increased, the local stress is reduced, and the blade collapse problem is improved, on the other hand, the cutting amount and cutting pressure of each section of the cutting edge can be adjusted according to the design of the length and angle of each section of the cutting edge. For example, the third cutting edge 6 has a serious collapse problem, the length of the second cutting edge 5 can be extended to reduce the cutting amount of the third cutting edge 6, or the spatial included angle of the two sections of the third cutting edge 6 can be reduced to reduce the cutting pressure of the third cutting edge 6. Both adjustment methods can improve the collapse problem of the third cutting edge 6.

[0036] In addition, it should be understood that although the present specification is described in terms of embodiments, not every embodiment contains only one independent technical solution, and the description of the specification is only for the sake of clarity, and those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can be combined appropriately to form other embodiments that those skilled in the art can understand.

Claims

1. A miniature drill bit, comprising a drill tip, characterized in that, The drill tip includes two short transverse cutting edges arranged symmetrically at the center. At least one first cutting edge with a different gradient than the short transverse cutting edge is provided at one end of the short transverse cutting edges that is far apart from each other. If there are multiple first cutting edges, the gradients between the multiple first cutting edges are not the same. The included angle between the two short transverse cutting edges is 140~170°, and the included angle between the two first cutting edges is 140~170°, and the included angle between the two first cutting edges is less than or equal to the included angle between the two short transverse cutting edges. The cutting surface corresponding to one or more segments of the first cutting edge is the first cutting edge. One segment of the first cutting edge corresponds to one first cutting edge, and multiple segments of the first cutting edge correspond to multiple first cutting edges on different planes. The intersecting edge of the first cutting edge with the spiral chip removal groove forms the second cutting edge. The second cutting edge is formed by intersecting with the first cutting edge.

2. The miniature drill bit according to claim 1, characterized in that, The included angle between the first cutting edge and the spiral chip removal groove is in the range of 50~70°.

3. The miniature drill bit according to claim 1, characterized in that, The spatial angle between the two corresponding second cutting edges is 90~150°, and the spatial angle between the two second cutting edges is less than or equal to the angle between the two first cutting edges.

4. The miniature drill bit according to claim 1, characterized in that, At least one third cutting edge with a gradient different from the second cutting edge is provided at one end of the second cutting edge that is far away from each other. If there are multiple third cutting edges, the gradients of the multiple third cutting edges are not the same.

5. The miniature drill bit according to claim 4, characterized in that, The spatial angle between the two segments of the third cutting edge is 50~150°, and the spatial angle between the two segments of the third cutting edge is less than or equal to the spatial angle between the two segments of the second cutting edge.

6. The miniature drill bit according to claim 4, characterized in that, The third cutting edge is formed by intersecting with the spiral chip removal groove, and the included angle between the third cutting edge and the spiral chip removal groove is 30~60°.

7. The miniature drill bit according to claim 1, characterized in that, The included angle between the first cutting edge and the second cutting edge is 90° to 130°.

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