A micro drill bit

Abstract

The present invention is applicable to the technical field of drill bit structure, and discloses a micro drill bit, including a drill shank and a drill body arranged at one end of the drill shank, the drill body including a cutting part and a guide part, the guide part is located between the cutting part and the drill shank, the cutting part includes two main cutting edges and spiral grooves corresponding to the two main cutting edges, the two main cutting edges are arranged on the end face of the cutting part, the two spiral grooves spirally extend from the end face of the cutting part in the direction of the guide part and intersect and stop at the front end of the guide part, the guide part is provided with a main chip groove and a secondary chip groove spirally extending from the front end of the guide part in the direction of the drill shank, and the front ends of the main chip groove and the secondary chip groove are both connected to the intersection of the two spiral grooves. The micro drill bit provided by the present invention can improve the overall rigidity of the drill bit, effectively solve the problem of broken blades in the process of PCB drilling, and can also improve the dimensional accuracy of the processed hole position.

Description

Technical Field

[0001] The invention belongs to the technical field of drill bit structures, and in particular relates to a micro drill bit. Background Art

[0002] With the halogen-free and environmentally friendly requirements for PCB boards, the processing difficulty is increasing. The anti-breakage performance and hole position requirements of ultra-small drills below Φ≤0.20 are getting higher and higher.

[0003] At present, in terms of the anti-breakage performance of ultra-small drill bits, single-slot drill bits have obvious advantages over conventional double-edged ordinary drill bits. However, the improvement of single-slot drill bits is limited to adjusting the spiral angle and core thickness taper to balance the drill bit rigidity and dust removal performance; therefore, for small drill bits for PCBs below Φ≤0.20, a structure that can improve the dust removal performance without reducing the drill bit rigidity is very meaningful for the design of small drill bits below Φ≤0.20. Summary of the invention

[0004] The present invention aims to solve at least one of the above-mentioned technical problems and provides a micro drill bit, which can improve the overall rigidity of the drill bit, effectively solve the problem of broken blades during PCB drilling, and improve the dimensional accuracy of the processed holes.

[0005] The technical solution of the present invention is: a micro drill bit, including a drill shank and a drill body arranged at one end of the drill shank, the drill body including a cutting part and a guide part, the guide part is located between the cutting part and the drill shank, the cutting part includes two main cutting edges and spiral grooves corresponding to the two main cutting edges, the two main cutting edges are arranged on the end face of the cutting part, the two spiral grooves spirally extend from the end face of the cutting part toward the guide part and intersect and stop at the front end of the guide part, the guide part is parallelly provided with a main chip groove and a secondary chip groove spirally extending from the front end of the guide part toward the drill shank, and the front ends of the main chip groove and the secondary chip groove are both connected to the intersection of the two spiral grooves.

[0006] Optionally, the length of the main chip flute is greater than the length of the auxiliary chip flute, and the main chip flute spirally extends to the rear end of the guide portion.

[0007] Optionally, the helix angles of the main chip flute and the secondary chip flute are both 30°-60°.

[0008] Optionally, the groove depths of the main chip groove and the auxiliary chip groove gradually decrease from the front end of the guide portion toward the drill shank.

[0009] Optionally, the drill body includes a first drill core and a second drill core, the first drill core is the part from the front end of the cutting part to the end position of the secondary chip groove, and the second drill core is the part from the end position of the secondary chip groove to the end position of the main chip groove, and the first drill core is a forward cone structure, and the second drill core is a flat cone structure.

[0010] Optionally, the taper of the first drill core is 0.001-0.004.

[0011] Optionally, the relationship among the first drill core length L, the main chip flute length L1 and the secondary chip flute length L2 is: L≤L2<L1.

[0012] Optionally, the first drill core length L is 70%-100% of the main chip flute length L1.

[0013] Optionally, the guide portion is provided with a reduced diameter section, the diameter of the reduced diameter section is 80%-95% of the diameter of the cutting portion, and the length of the reduced diameter section is less than or equal to the length L2 of the secondary chip removal groove.

[0014] Optionally, the length of the cutting portion is less than or equal to 0.5 mm.

[0015] The micro drill provided by the present invention has a cutting part designed as a double cutting edge structure, so that the two spiral grooves of the cutting part intersect and stop at the front end of the guide part, and two parallel main chip grooves and auxiliary chip grooves are arranged on the guide part and the front end is connected to the intersection of the two spiral grooves of the cutting part to remove chips, thereby reducing the amount of cutting of the drill body base, wherein the auxiliary chip groove plays a role in increasing the chip space and assisting the main chip groove in chip removal, thereby avoiding chip blockage, and at the same time, the drill core of the drill body is designed as a tapered structure with a gradually increasing diameter, which can enhance the rigidity of the middle and rear sections of the drill bit and effectively reduce the probability of broken edges during drilling. It improves the anti-broken edge performance of the drill bit and the dimensional accuracy of hole processing. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0017] Figure 1 is a schematic structural diagram of a micro drill provided by an embodiment of the present invention;

[0018] Figure 2 It is a schematic structural diagram of a reduced diameter section of a guide portion in a micro drill provided by an embodiment of the present invention;

[0019] Figure 3 It is a structural schematic diagram of a first drill core and a second drill core in a drill body of a micro drill provided by an embodiment of the present invention;

[0020] Figure 4 It is a cross-sectional schematic diagram of a spiral groove, a main chip removal groove and a secondary chip removal groove in a micro drill provided by an embodiment of the present invention;

[0021] Figure 5 This is another structural schematic diagram of a micro drill provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0022] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0023] It should be noted that the terms “setting” and “connection” should be understood in a broad sense. For example, it can be directly setting or connecting, or it can be indirectly setting or connecting through a central component or a central structure.

[0024] In addition, in the embodiments of the present invention, if there are terms indicating orientation or positional relationships such as "longitudinal", "transverse", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., they are based on the orientation or positional relationships or conventional placement states or usage states shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the structure, feature, device or element referred to must have a specific orientation or positional relationship, nor must it be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0025] The various specific technical features and embodiments described in the specific implementation methods can be combined in any suitable manner unless there is any contradiction. For example, different implementation methods can be formed by combining different specific technical features / embodiments. In order to avoid unnecessary repetition, the various possible combinations of the specific technical features / embodiments in the present invention will not be described separately.

[0026] like Figure 1 and Figure 5As shown, a micro drill bit provided in an embodiment of the present invention belongs to a UC type drill bit, which is mainly used for hole processing of PCB boards with a hole diameter of less than 0.2 mm, and includes a drill handle 1 and a drill body 2 arranged at one end of the drill handle 1, wherein the drill body 2 includes a cutting portion 21 for drilling processing and a guide portion 22 for guiding and removing chips during drilling, wherein the guide portion 22 is located between the cutting portion 21 and the drill handle 1, and the cutting portion 21 includes two main cutting edges 211 and spirals corresponding to the two main cutting edges 211. Groove 212, the two main cutting edges 211 are arranged on the end surface of the cutting portion 21, the two spiral grooves 212 spirally extend from the end surface of the cutting portion 21 toward the guide portion 22 and intersect and stop at a point at the front end of the guide portion 22, and the guide portion 22 is parallelly provided with a main chip groove 221 and a secondary chip groove 222 spirally extending from the front end of the guide portion 22 toward the drill shank 1, and the front ends of the main chip groove 221 and the secondary chip groove 222 are both connected to the intersection of the two spiral grooves 212. By adopting the cutting part 21 with a double-edged structure, during drilling, the two main cutting edges 211 have a fast drilling speed, balanced force, are not prone to vibration, have good drilling stability, and can effectively ensure the smoothness of the hole wall of the processed hole. The chips generated by the drilling of the cutting part 21 are discharged by the two spiral grooves 212 to the main chip groove 221 provided on the guide part 22, and the chips are discharged by the main chip groove 221. In this way, the amount of cutting of the drill body 2 matrix during the processing of the drill bit can be effectively reduced, the rigidity of the drill body 2 of the drill bit can be enhanced, and the probability of broken edges can be reduced. At the same time, in order to further improve the chip removal efficiency, a secondary chip groove 222 parallel to the main chip groove 221 is provided on the guide part 22, so that the part of the guide part 22 in the PCB board has sufficient chip accommodating space, and the main chip groove 221 can also be assisted in chip removal, thereby improving the overall chip removal performance of the drill bit and ensuring the dimensional accuracy of the processed hole.

[0027] In practical applications, the drill shank 1 and the drill body 2 can be connected via an inclined portion having a conical structure.

[0028] Alternatively, if Figure 1As shown, the length of the main chip groove 221 is greater than the length of the auxiliary chip groove 222, and the main chip groove 221 spirally extends to the rear end of the guide portion 22. The length of the main chip groove 221 is greater than the length of the auxiliary chip groove 222, and the amount of cutting of the drill body 2 base is reduced under the premise of ensuring smooth chip removal, and the rigidity of the drill body 2 is further improved, wherein the main chip groove 221 is spirally extended to the rear end of the guide portion 22 (or the main chip groove 221 is spirally extended to the connection between the tool handle and the drill body 2), so as to ensure that during the drilling process, the main chip groove 221 still has a certain length exposed above the surface of the PCB board, which is conducive to the discharge of chips from the hole. In actual application, when the cutting portion 21 generates a large amount of chips in a short time, in order to avoid chips being blocked in the chip removal of the guide portion 22, the auxiliary chip groove 222 can be designed to be equal in length to the main chip groove 221.

[0029] Alternatively, if Figure 1 As shown, the helix angle β of the main chip groove 221 and the auxiliary chip groove 222 is 30°-60°. Under the condition of ensuring the rigidity of the drill body, by optimizing the helix angle β of the main chip groove 221 and the auxiliary chip groove 222, it is beneficial for the chips to be discharged smoothly from the hole, ensuring the smooth drilling process. In the embodiment of the present invention, the helix angle β of the main chip groove 221 and the auxiliary chip groove 222 is 45°±2°.

[0030] Alternatively, if Figure 4 As shown, from the front end of the guide portion 22 toward the drill shank 1, the groove depths of the main chip groove 221 and the secondary chip groove 222 gradually decrease, that is, the groove depths of the main chip groove 221 and the secondary chip groove 222 at the front end of the guide portion 22 are greater than the groove depths at the end position of the secondary chip groove 222 or the end position of the main chip groove 221, and at the same axial position of the guide portion 22, the groove depths of the main chip groove 221 and the secondary chip groove 222 are consistent.

[0031] Alternatively, if Figure 3 As shown, the drill body 2 includes a first drill core 3 and a second drill core 4, wherein the first drill core 3 is the portion from the front end of the cutting portion 21 to the end position of the secondary chip flute 222, and the second drill core 4 is the portion from the end position of the secondary chip flute 222 to the end position of the primary chip flute 221, and the first drill core 3 is a forward cone structure, and the second drill core 4 is a flat cone structure. The first drill core 3 (the front end of the drill body 2) is designed as a forward cone structure to increase the rigidity of the middle and rear sections of the drill body 2, ensure that the cutting portion 21 has good positioning accuracy during the machining process, improve the dimensional accuracy of the drilled hole, and effectively improve the overall rigidity and bending resistance of the drill bit. In practical applications, the second drill core 4 can also be a forward cone structure.

[0032] Optionally, the taper of the first drill core 3 is 0.001-0.004, and the taper of the first drill core 3 can be determined according to the cutting rate of the cutting portion 21, so that the strength performance of the drill body 2 meets the processing requirements. And the forward-cone structure design of the first drill core 3 increases the root groove width ratio of the reduced diameter portion (the root groove width refers to the distance of the chip groove rotating one circle along the axial direction), which can effectively increase the chip space of the chip groove. In the embodiment of the present invention, the taper of the first drill core 3 is 0.002, and the taper of the second drill core 4 is 0. It can be understood that the second drill core 4 can also be designed as a forward-cone structure according to actual needs.

[0033] Alternatively, if Figure 1 and Figure 3 As shown, the relationship between the first drill core length L, the main chip flute length L1 and the secondary chip flute length L2 is: L≤L2<L1, and the first drill core length L is 70%-100% of the main chip flute length L1. By optimizing the first drill core length L, the main chip flute length L1 and the secondary chip flute length L2, it is ensured that the first drill core 3 has sufficient rigidity and the chip removal performance of the guide part 22. In the embodiment of the present invention, the first drill core length L is 80% of the main chip flute length L1.

[0034] Alternatively, if Figure 2 As shown, the guide portion 22 is provided with a reduced diameter section 223, the diameter D2 of the reduced diameter section 223 is 80%-95% of the diameter D1 of the cutting portion 21, and the length of the reduced diameter section 223 is equal to the length L2 of the secondary chip removal groove. Since the diameter D2 of the guide portion 22 at the reduced diameter section 223 is smaller than the diameter D1 of the cutting portion 21, during drilling, there is a gap between the guide portion 22 and the hole wall of the processing hole, which avoids the friction between the guide portion 22 and the hole wall to generate heat, thereby ensuring the processing quality of the hole and improving the finish of the hole wall. In the embodiment of the present invention, the diameter of the reduced diameter section 223 is 90% of the diameter D1 of the cutting portion 21.

[0035] Alternatively, if Figure 1 As shown, the length L3 of the cutting portion 21 is less than or equal to 0.5 mm. The cutting portion 21 is used for drilling processing, and has high requirements on processing accuracy and structural rigidity. In order to reduce production costs, the length L3 of the cutting portion 21 needs to be controlled, and the cutting portion 21 should not be designed to be too long.

[0036] Alternatively, if Figure 1As shown, the helix angle α of the two spiral grooves 212 is 25°-50°, and the two spiral grooves 212 are symmetrically arranged about the axis of the cutting portion 21. The drill bit can have a double cutting edge structure, and the drilling process can be well realized. By optimizing the helix angle α of the spiral groove 212, the chip removal performance of the cutting portion 21 can be effectively improved to avoid chip blockage and chip breakage of the main cutting edge 211. At the same time, effective heat dissipation can be achieved to avoid excessive temperature of the main cutting edge 211 during the cutting process.

[0037] Specifically, the cutting portion 21 may be coated with a coating, which can effectively reduce the friction and heat generation of the cutting portion 21 during drilling and increase the service life of the drill bit. In an embodiment of the present invention, the coating is a DLC coating.

[0038] In practical applications, according to different processing methods, that is, different processing sequences of the main chip groove 221 and the auxiliary chip groove 222, the obtained drill bit has different structures, such as Figure 1 As shown in FIG. 1 , the main chip groove 221 is processed first, and then the secondary chip groove 222 is processed. The end position of the secondary chip groove 222 in the drill bit is located behind the main chip groove 221. As shown in FIG. 5 , the secondary chip groove 222 is processed first, and then the main chip groove 221 is processed. The end position of the secondary chip groove 222 in the drill bit is located in front of the main chip groove 221. Although the chip groove position structures of the two drill bits are different, the functions realized by the two and the technical effects obtained are the same.

[0039] A micro drill provided by an embodiment of the present invention designs the cutting part 21 into a double cutting edge structure, so that the two spiral grooves 212 of the cutting part 21 intersect and stop at the front end of the guide part 22, and two parallel main chip grooves 221 and auxiliary chip grooves 222 are arranged on the guide part 22 and the front end is connected to the intersection of the two spiral grooves 212 of the cutting part 21 to remove chips, thereby reducing the amount of cutting of the drill body 2 base, wherein the auxiliary chip groove 222 increases the chip space and assists the main chip groove 221 in chip removal, thereby avoiding chip blockage, and at the same time, the drill core of the drill body 2 is designed as a tapered structure with a gradually increasing diameter, which can enhance the rigidity of the middle and rear sections of the drill bit and effectively reduce the probability of broken edges during drilling. It improves the anti-broken edge performance of the drill bit and the dimensional accuracy of hole processing.

[0040] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modification, equivalent substitution or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A micro drill bit, comprising a drill shank and a drill body arranged at one end of the drill shank, characterized in that: The drill body comprises a cutting portion and a guide portion, wherein the guide portion is located between the cutting portion and the drill shank, the cutting portion comprises two main cutting edges and spiral grooves corresponding to the two main cutting edges, the spiral angles of the two spiral grooves are 25°-50°, the two spiral grooves are symmetrically arranged about the axis of the cutting portion, the two main cutting edges are arranged on the end face of the cutting portion, the two spiral grooves spirally extend from the end face of the cutting portion toward the guide portion and intersect and stop at the front end of the guide portion, the guide portion is parallelly provided with a main chip removal groove and a secondary chip removal groove spirally extending from the front end of the guide portion toward the drill shank, and the front ends of the main chip removal groove and the secondary chip removal groove are both connected to the intersection of the two spiral grooves; The secondary chip groove is parallel to the main chip groove, the length of the main chip groove is greater than the length of the secondary chip groove, and the main chip groove spirally extends to the rear end of the guide portion; the helical angles of the main chip groove and the secondary chip groove are both 30°-60°; from the front end of the guide portion toward the drill shank, the groove depths of the main chip groove and the secondary chip groove gradually decrease; The drill body includes a first drill core and a second drill core, the first drill core is the part from the front end of the cutting part to the end position of the secondary chip groove, and the second drill core is the part from the end position of the secondary chip groove to the end position of the main chip groove, the second drill core is a flat cone structure, and the first drill core is a forward cone structure; the taper of the first drill core is 0.001-0.004; the length L of the first drill core is 80% of the length L1 of the main chip groove; the guide part is provided with a reduced diameter section.

2. A micro drill as claimed in claim 1, characterized in that: The diameter of the reduced diameter section is 80%-95% of the diameter of the cutting portion, and the length of the reduced diameter section is less than or equal to the length L2 of the secondary chip removal groove.

3. A micro drill as claimed in claim 1 or 2, characterized in that: The length of the cutting portion is less than or equal to 0.5 mm.

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