WO2015165136A1

WO2015165136A1 - Pcb micro drill

Info

Publication number: WO2015165136A1
Application number: PCT/CN2014/078446
Authority: WO
Inventors: 屈建国; 薛倩; 王磊; 邹卫贤
Original assignee: 深圳市金洲精工科技股份有限公司
Priority date: 2014-04-30
Filing date: 2014-05-26
Publication date: 2015-11-05
Also published as: CN105014124B; CN105014124A

Abstract

A PCB micro drill comprises a drill body (1), at most three main cutting edges (212, 212', 221), and a composite drill tip (2) located at one end of the drill body. The composite drill tip comprises a first drill tip (21) and a second drill tip (22). The second drill tip is disposed at an end portion of the drill body. The first drill tip starts from the top end of the second drill tip and extends and protrudes outwards in the direction parallel to the central axis of the drill body. The first drill tip comprises a chisel edge (211) intersecting with the central axis of the drill body, an inner main cutting edge (212) connected to an end portion of the chisel edge, and a first inner vertex angle rear tool surface (213) clamped between the inner main cutting edge and the chisel edge. According to the micro drill, the drill tip is the composite drill tip consisting of the first drill tip and the second drill tip. The composite drill tip improves the centering effect of downward drilling during hole site machining for the PCB micro drill, improves the hole site accuracy, and prevents a failure in a hole site or a hole shape.

Description

PCB micro drill

Technical field

The invention relates to the technical field of micro drill bits, in particular to a PCB micro drill.

Background technique

The development trend of light, thin, short and small modern electronic components and the increasingly high reliability requirements make the requirements of drilling and hole positioning precision and hole wall quality of printed circuit board (PCB) plates Improvement, and the structure of existing PCB micro-drills has been in a very mature stage after a period of development and evolution. However, as the requirements of the application market continue to increase and change, PCB drilling technology has entered a stage that is both an opportunity and a challenge, and the limitations of the existing drill bit structure of PCB drill bits have led to the development of PCB drilling technology. Enter the bottleneck stage.

There are several limitations to the existing PCB micro drill tip structure:

1) When the top angle is small, the hole position is favorable due to the better centering during the drilling, but during the drilling process, the radial component of the drilling is large, and the wall of the hole is stressed; the chip is wide and difficult to discharge; the main cutting edge The sharp edge of the main edge at the turning point of the outer edge is large, and the hole is not sharp enough when drilling, and the hole wall problem such as rough hole wall, wick, nail head, glass fiber pulling, anode conductive wire failure, etc.;

2) When the apex angle is large, although it is beneficial to improve the quality of the hole wall, it will result in short main cutting edge, long horizontal blade length, centering instability during drilling while drilling, easy sliding knife, poor hole position accuracy; drilling process The large axial pressing force is easy to cause problems such as broken knife and excessive wear of the drill tip;

3) Due to the small diameter of the micro-drill, in order to increase the resistance to the broken knife and ensure the accuracy of the hole position, it is necessary to increase the core diameter ratio to ensure a sufficiently strong rigidity, but the length of the chisel edge is long and the main cutting edge is short, resulting in The following two adverse consequences: First, the centering difference when drilling, easy to slide, affecting the accuracy of the hole position; Second, because the main cutting edge is short, the extrusion is serious during cutting, the cutting force is large, it is not easy to break the chip, easy to cause The consequences of entanglement and broken knife;

Due to the above limitations of the existing PCB micro-drilling drill-tip structure, it is difficult for the micro-drill of the conventional drill-tip structure to achieve the ultimate comprehensive performance of the anti-breaking knife performance, the hole position precision and the hole wall quality in the drilling process. This is the bottleneck problem faced by the existing PCB micro drill tip structure design.

technical problem

The object of the present invention is to provide a PCB micro-drill, which aims to solve the limitation of the above-mentioned PCB micro-drilling drill tip structure in the prior art, which makes it difficult to simultaneously comprehensively resist the performance of the broken knife, the accuracy of the hole position and the quality of the hole wall. Achieve the ultimate problem.

Technical solution

The present invention is achieved in that a PCB micro drill is provided, including a drill body, and a main cutting edge or two main cutting edges or three main cutting edges, and the PCB micro drill further includes a composite at one end of the drill body. a drill tip, the composite drill tip includes a first drill tip and a second drill tip, the second drill tip is disposed at an end of one end of the drill body, and the first drill tip starts from the second drill a tip end extending outwardly in a direction parallel to a central axis of the drill body, the first drill tip including a chisel edge intersecting the central axis of the drill body, the end of the chisel edge The inner main cutting edge and the first inner top corner flank sandwiched between the inner main cutting edge and the chisel edge.

Preferably, the first drill tip further includes a second inner corner flank face on a side of the first inner corner flank face and contacting the chisel edge, the first inner corner angle The flank face and the second inner top corner flank face are obliquely intersected to form an inner apex angle.

Further, the second drill tip includes a first flank face outside the flank face of the first inner apex angle, and a side edge formed on the first flank face and the inner main cutting The main cutting edge connected to one end of the blade.

Further, the second drill tip further includes a second flank face between the first flank face and the second inner apex flank face and intersecting with the two, the outline of the second drill tip Form the outer corner.

Further, a position is set between the first flank face and the first inner apex flank face, and the second flank face and the second inner apex angle flank face are at the same angle .

Further, the first flank face and the outer wall of the drill body, and the second flank face and the outer wall of the drill body are disposed at the same angle.

Further, the inner apex angle is smaller than the outer apex angle.

Further, the inner apex angle is greater than or equal to 60 degrees and less than or equal to 130 degrees; and the outer apex angle is greater than or equal to 110 degrees and less than or equal to 180 degrees.

Preferably, a distance between a bottom edge of the first inner corner flank and a bottom edge of the second inner corner flank is d ₁ , and an outer diameter of the PCB micro drill is d ₂ . And 10% ≤ d ₁ / d ₂ ≤ 90%.

Further, the outer wall of the drill body is spirally disposed with a spiral chip flute starting from the first drill tip and extending along the axis of the drill body toward the tail end thereof.

Beneficial effect

The PCB micro-drill proposed by the invention divides the drill tip at the end of the drill body into two, forming a composite drill tip composed of a first drill tip and a second drill tip, and improves the PCB through a specially designed composite drill tip. The micro-drilling centering effect of the drill while drilling the hole position improves the hole position precision, avoids the hole position and hole shape caused by the squeegee, and improves the quality of the hole wall.

DRAWINGS

1 is a partial perspective view of a double-edged PCB micro drill according to an embodiment of the present invention;

2 is a front view of a double-edged PCB micro drill according to an embodiment of the present invention;

3 is a schematic diagram showing a top angle profile of a double-edged PCB micro drill according to an embodiment of the present invention;

4 is a front view of a single-blade PCB micro drill 1 according to an embodiment of the present invention;

FIG. 5 is a partial perspective view of a single-blade PCB micro drill 1 according to an embodiment of the present invention; FIG.

6 is a front view of a single-blade PCB micro drill 2 according to an embodiment of the present invention;

7 is a partial perspective view of a single-blade PCB micro drill 2 according to an embodiment of the present invention;

FIG. 8 is a front view of a single-blade PCB micro drill 3 according to an embodiment of the present invention; FIG.

FIG. 9 is a partial perspective view of a single-blade PCB micro drill 3 according to an embodiment of the present invention;

10 is a front view of a single-blade PCB micro drill 4 according to an embodiment of the present invention;

11 is a partial perspective view of a single-blade PCB micro drill 4 according to an embodiment of the present invention;

12 is a front view of a single-blade PCB micro drill 5 according to an embodiment of the present invention;

13 is a partial perspective view of a single-blade PCB micro drill 5 according to an embodiment of the present invention;

14 is a front view of a single-blade PCB micro drill 6 according to an embodiment of the present invention;

15 is a partial perspective view of a single-blade PCB micro drill 6 according to an embodiment of the present invention;

16 is a front view of a three-blade PCB micro drill according to an embodiment of the present invention;

FIG. 17 is a partial perspective view of a three-blade PCB micro drill according to an embodiment of the present invention.

Embodiments of the invention

The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It is understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

The implementation of the present invention will be described in detail below with reference to the specific drawings.

The technical solution described in the present invention is applicable to single-blade, double-blade, and three-blade PCB micro drills, which will be described below by way of specific embodiments.

Embodiment 1:

In this embodiment, as shown in FIG. 1 to FIG. 3, it is a double-edged PCB micro drill.

As shown in FIG. 1 , the PCB micro drill of the embodiment includes a drill body 1 and a composite drill tip 2 , and the composite drill tip 2 is located at the end of the drill body 1 . Specifically, the composite drill tip 2 includes a first drill tip. 21 and a second drill point 22, wherein the second drill point 22 is disposed at one end of the drill body 1, the first drill point 21 starts at the top end of the second drill point 22, and along the central axis of the drill body 1 The parallel directions extend outwardly and protrude.

As shown in FIG. 2, the first drill tip 21 includes a chisel edge 211, an inner main cutting edge 212, a first inner corner flank 213 and a second inner corner flank 214, wherein the chisel edge 211 and the drill body 1 center axis crossing, inner main cutting edge 212 is connected to one end of the chisel edge 211, and the first inner corner flank 213 is sandwiched between the chisel edge 211 and the inner main cutting edge Between 212, or in other words, the chisel edge 211 and the inner major cutting edge 212 are respectively formed by two connected edges of the first inner corner flank 213, and the second inner corner flank 214 is located at the first inner top. The corner flank 213 is to the right and intersects with it, while the lower edge of the second inner apex flank 214 is in contact with the chisel edge 211.

The first inner corner flank 213 and the second inner corner flank 214 are connected to form a first drill tip surface 210. For the double edge type PCB micro drill in this embodiment, the first drill The tip 21 includes two tip faces, a first tip face 210, and a first tip face 210' that is centrally symmetrical with the first tip face 210, the first tip face 210' including a first inner tip angle a flank 213' and a second inner apex flank 214', wherein the first inner apex flank 213 and the first inner apex flank 213' are centrally symmetrical, and the second inner apex flank 214 and the second inner apex flank 214' are centrally symmetrical, and the edge of the first inner apex flank 213' is formed with an inner major cutting edge 212' that is symmetrical with the center of the inner major cutting edge 212, and Blade 211 center symmetric and connected chisel edge 211', where the center of symmetry is the central axis of the drill body 1.

Referring to FIG. 2 and FIG. 3, the first inner corner flank 213 and the second inner corner flank 214' intersect to form a chisel edge 211, and the two planes are inclined at an angle, and the angle is an inner top. angle σ _1; in the same manner, a first inner flank 214 and the inner top corner rake surface after the second apex 213 'formed in a cross-intersection edge 211', which also showed a certain angle between the two planes inclined to each other, and the clip The angle is also the inner apex angle σ ₁ .

The above-mentioned PCB micro-drilling is used for drilling, which has the following characteristics:

1) Dividing the drill tip portion into two, forming a first drill tip 21 and a second drill tip 22, and by providing the first drill tip 21 protruding from the second drill tip 22, the chisel edge 211 is improved when drilling The force is increased, the radial component of the drill tip is increased during the drilling, and the material to be processed is discharged along the radial force to both sides, which improves the centering effect when drilling, and effectively prevents the drill tip from slipping. Thereby obtaining better hole position and hole type precision;

2) Dividing the drill tip portion into two, forming a first drill tip 21 and a second drill tip 22, by setting a second drill tip 22, the main blade tip angle is reduced, that is, the angle between the main cutting edge and the outer wall of the drill body is reduced, so that the cutting edge is sharper during cutting, the friction between the main hole and the hole wall is reduced, and the hole is reduced. The problem of wall roughness, burr, and fiberglass pulling the wall improves the quality of the hole wall.

As shown in FIG. 2, in the embodiment, the second drill tip 22 includes a main cutting edge 221, a first flank surface 222, and a second flank surface 223, wherein the main cutting edge 221 is disposed on the inner main cutting edge. The outer end of the 212 is connected to the outer end, and the first flank 222 is located outside the first inner corner flank 213 and intersects with the second flank 223, and the second flank 223 is clamped to the second inner corner Between the face 214 and the first flank face 222, and the second flank face 223 respectively intersect the two planes, the main cutting edge 221 is formed on one side edge of the first flank face 222, and the first flank face 222 And intersecting with the second flank 223 to form a second drill face 220. Here, since the PCB micro drill in this embodiment is a double-edged micro drill, the second drill tip 22 includes the second drill face 220. And a second drill face 220' symmetrical with the center of the second drill face 220, where the second drill face 220' includes a first flank 222' and a second flank 223', wherein The flank face 222' and the first flank face 222 are centrally symmetrical, and the second flank face 223' and the second flank face 223 are centrally symmetrical, where the center of symmetry is the drill body 1 Heart axis.

The second drill tip 22 is contoured to form an outer apex angle σ ₂ . Specifically, referring to FIG. 2 and FIG. 3, the first flank face 222 and the first flank face 222' are inclined at an angle, and the included angle is also an outer apex angle σ ₂ .

In this embodiment, the first flank 222 intersects with the first inner corner flank 213, and the angle between the two is inclined at an angle, and the second flank 223' and the second inner corner The flank faces 214' intersect, the two are also inclined at a certain angle, and the angles of the two are equal; in addition, the first flank face 222' intersects with the first inner apex flank face 213', and The angle between the two is inclined at an angle, and the second flank 223 and the second apex angle 214 intersect with each other, and the two are inclined at a certain angle, and the angles of the two are equal.

As shown in FIG. 3, the first flank 222 and the outer wall of the drill body 1 form an angle θ, since the first flank 222 and the first flank 222' are center-symmetric with respect to the center axis of the drill body 1. Therefore, the first flank surface 222' and the outer wall of the drill body 1 also form an angle θ. Referring to FIG. 2, since the main cutting edge 221 is located at one side edge of the first flank surface 222, The main blade sharp angle formed between the main cutting edge 221 and the outer wall of the drill body 1 is also θ; similarly, the main blade sharp angle formed between the main cutting edge 221' and the outer wall of the drill body 1 is also θ.

In this embodiment, referring to FIG. 3, the inner apex angle σ ₁ formed by the intersection of the first inner corner flank 213 and the second inner corner flank 214 ′ is smaller than the first flank 222 and The outer apex angle σ ₂ formed between the first flank faces 222' is σ ₁ < σ ₂ .

In the embodiment, for the first drill tip 21, the inner apex angle σ ₁ formed by the intersection of the first inner corner flank surface 213 and the second inner corner flank surface 214 ′, or The inner apex angle σ ₁ formed by the intersection of the first inner corner flank 213' and the second inner apex flank 214, the inner apex angle σ ₁ is designed to be: 60° ≤ σ ₁ ≤ 130°, Within the range of values, the inner apex angle σ ₁ can be obtained according to actual needs. When the inner apex angle σ _{1 is} decreased, the negative rake angle of the chisel edge 211 is reduced by about 40%, and a length is added. It is about 50% of the cutting edge of the original cutting edge, that is, the inner main cutting edge 212 described above, and the length of the main cutting edge 211 is increased by about 10%. The structural design of the first drill tip 21 improves the force of the chisel edge 211 during drilling, increases the radial component of the drill tip during the drilling, and causes the material to be processed to be discharged to both sides along the radial force. It improves the centering effect when drilling, effectively prevents the drill tip from slipping, and improves the hole position and hole type accuracy.

For the second drill point 22, an outer apex angle σ ₂ is formed between the first flank face 222 and the first flank face 222', and the outer apex angle σ _{2 is} designed to be: 110° ≤ σ ₂ ≤180°, within the range of values, the outer apex angle σ ₂ can obtain a larger value according to actual needs, while ensuring σ ₁ < σ ₂ , when the outer apex angle σ ₂ increases, the above-mentioned main edge sharp angle The θ is reduced, so that the entire blade portion is sharper, thereby effectively reducing the friction between the drill tip portion and the hole wall during drilling, and avoiding some hole wall problems, such as hole wall roughness, burr, and glass fiber. Pull and so on.

During drilling, the outer apex angle σ ₂ achieves a large value within the range of its value, and the radial force of the entire composite drill tip 2 is reduced, and the axial force is increased, thereby facilitating smooth drilling of the drill body. This increases the layer protection for the hole position and the hole shape. At the same time, the front angle of the main cutting edge 221 is increased, the drill bit is sharper, the impact force on the hole wall is smaller, and the length of the main cutting edge 221 is increased, which is effective. The problem of wall quality such as rough wall, wick, nail head, glass fiber pulling, and anode conductive wire failure is solved.

As shown in FIG. 3, the distance between the bottom edge of the first inner corner flank 213 and the bottom edge of the second inner corner flank 214' is d ₁ , and the first inner corner flank The distance between the bottom edge of the 213' and the bottom edge of the second inner corner flank 214 is d ₁ , and the drill diameter of the PCB micro drill is d ₂ . In this embodiment, the ratio of the ratio of d ₁ to d ₂ Selection: 10% ≤ d ₁ / d ₂ ≤ 90%, thus effectively ensuring the centering effect of the entire composite drill tip 2, of course, in other embodiments, depending on the actual situation and needs, d ₁ /d ₂ can also Other ratios are not limited to the preferred range values in this embodiment.

As shown in FIG. 1 , in the embodiment, the PCB micro drill further includes a chip flute 3 that is spirally disposed on an outer wall of the drill body 1 , and the chip flute 3 starts from the first drill. a tip 21 extending along the axis of the drill body 1 toward its tail end. In addition, the chip flute 3 is spiral. In different embodiments, the drill body 1 is provided with one or more flutes 3, No details are given.

Embodiment 2:

As shown in Figures 4 to 15, there are six cases of single-edge PCB micro-drilling.

Referring to FIG. 4 and FIG. 5, a single-blade PCB micro-drilling one, the PCB micro-drilled composite drill tip 2 includes a first drill tip 21 and a second drill tip 22, the first drill tip 21 includes a chisel edge 211, an inner major cutting edge 212, a first inner corner flank 213 and a second inner corner flank 214, and another at the chisel edge a first inner corner flank 213' and a second inner corner flank 214' of the side; the second drill tip 22 includes a main cutting edge 221, a first flank 222 and a second flank 223, Single-blade PCB micro-drilling one, not detailed here.

Referring to FIG. 6 and FIG. 7, a single-blade PCB micro drill 2, the PCB micro-drilled composite drill tip 2 includes a first drill tip 21 and a second drill tip 22, the first drill tip 21 includes a chisel edge 211, an inner major cutting edge 212, a first inner corner flank 213 and a second inner corner flank 214, and another at the chisel edge a first inner corner flank 213' and a second inner corner flank 214' of the side; the second drill tip 22 includes a main cutting edge 221, a first flank 222 and a second flank 223, Single-blade PCB micro drill 2, not detailed here.

Referring to FIG. 8 and FIG. 9, a single-blade PCB micro drill 3, the PCB micro-drilled composite drill tip 2 includes a first drill tip 21 and a second drill tip 22, the first drill tip 21 includes a chisel edge 211, an inner major cutting edge 212, a first inner corner flank 213 and a second inner corner flank 214, and another at the chisel edge a first inner corner flank 213' and a second inner corner flank 214' of the side; the second drill tip 22 includes a main cutting edge 221, a first flank 222 and a second flank 223, Single-blade PCB micro drill 3, not detailed here.

Referring to FIG. 10 and FIG. 11 , a single-blade PCB micro drill 4 includes a first drill tip 21 and a second drill tip 22 , and the first drill tip 21 includes a chisel edge 211 and an inner lead. The cutting edge 212, the first inner corner flank 213 and the second inner corner flank 214, and the first inner corner flank 213' and the second inner corner flank on the other side of the chisel edge The second drill point 22 includes a main cutting edge 221, a first flank face 222, and a second flank face 223. For a single-blade type PCB micro-drill 4, it will not be described in detail herein.

Referring to FIG. 12 and FIG. 13 , a single-blade PCB micro drill 5 includes a first drill tip 21 and a second drill tip 22 , and the first drill tip 21 includes a chisel edge 211 and an inner lead. The cutting edge 212, the first inner corner flank 213 and the second inner corner flank 214, and the first inner corner flank 213' and the second inner corner flank on the other side of the chisel edge The second drill point 22 includes a main cutting edge 221, a first flank face 222, and a second flank face 223. For a single-blade type PCB micro-drilling five, it will not be described in detail herein.

Referring to FIG. 14 and FIG. 15, a single-edge PCB micro drill 6 includes a first drill tip 21 and a second drill tip 22, and the first drill tip 21 includes a chisel edge 211 and an inner main end. The cutting edge 212, the first inner corner flank 213 and the second inner corner flank 214, and the first inner corner flank 213' and the second inner corner flank on the other side of the chisel edge Face 214'; the second drill tip 22 includes a main cutting edge 221, a first flank face 222, and a second flank face 223. For a single-blade PCB micro-drill six, it will not be described in detail herein.

Embodiment 3:

As shown in FIGS. 16-17, the three-edge type PCB micro drill includes a first drill tip 21 and a second drill tip 22, and the first drill tip 21 includes a chisel edge 211 and an inner lead. Cutting edge 212, first inner corner flank 213; The second drill tip 22 includes a main cutting edge 221 and a first flank face 222. For a three-blade type PCB micro drill, it will not be described in detail herein.

For the above technical solution, the double-blade PCB micro-drill proposed in the first embodiment, the six single-blade PCB micro-drills proposed in the second embodiment, and the three-blade PCB micro-drill proposed in the third embodiment are all drilled through The tip portion is divided into two, forming a composite drill tip 2 composed of the first drill tip 21 and the second drill tip 22, while satisfying the reduction of the apex angle and the chisel edge length, increasing the cutting edge length and reducing the main edge The requirements of the sharp corners improve the resistance to the broken knife performance, the hole position accuracy and the quality of the hole wall in the PCB drilling technology through the design of the composite drill tip 2, thereby breaking the bottleneck stage of the PCB drilling technology and entering the new drill. Hole era.

The comparison test between the PCB micro drill and the conventional drill bit in the embodiment of the present invention is as follows:

For Comparative Test 1 and Comparative Test 2, the test tool is: conventional drill needle Φ0.30-5.5, drill bit Φ0.30-5.5 in the embodiment of the present invention; processing parameters are: S145krpm, F96ipm, U800ipm, H2000.

1) Comparison test 1: comparison of hole position accuracy.

The CPK value data of the hole in Comparative Experiment 1 is shown in Table 1 below:

Research times\hole position CPK value\drill needle	Embodiment of the present invention	Conventional drill
New knife	3.12	2.82
Kenichi	2.88	2.63
Research II	2.45	1.96
Kenzo	2.08	1.51

It can be seen from Table 1 that by analyzing the data, it is found that the burr performance of the embodiment of the present invention is excellent in the performance of the hole position during the processing, which is greatly improved compared with the conventional burr; the core diameter changes after the conventional burr is ground. The positioning performance is poor, and the hole position is obviously reduced. The burr of the embodiment of the invention overcomes this phenomenon by its unique structural design, and can maintain the high hole position performance during the high-order machining process.

2) Comparative test 2: nail head contrast.

The nail head data of Comparative Test 2 is shown in Table 2 below:

Research times\nail head data\drill needle	Embodiment of the present invention	Conventional drill
New knife	100%	123%
Kenichi	118%	138%
Research II	122%	146%
Kenzo	138%	155%

It can be seen from Table 2 that by analyzing the data, it is found that the drill needle of the embodiment of the present invention has a greater advantage in the nail head than the conventional drill needle, and the research is still within 1.4 times, which is suitable for the nail head. Highly demanding processing occasions.

For Comparative Test 3, the test tool is: conventional drill Φ 0.25-5.0, the drill bit of the embodiment of the present invention Φ0.25-5.0; its processing parameters are: S155krpm, F90ipm, U1000ipm, H2000.

3) Comparative test three: comparison of hole wall roughness.

The crude pore data of Comparative Experiment 3 is shown in Table 3 below:

Research times\hole coarse data (μm)\drill	Embodiment of the present invention	Conventional drill
New knife	8	15
Kenichi	10	18
Research II	9	20
Kenzo	11	twenty one

It can be seen from Table 3 that by analyzing the data, it is found that the drill needle of the embodiment of the present invention has a larger advantage in the hole thickness than the conventional drill needle, and can meet the processing requirements of the high hole height requirement.

For the comparative test four, the test tool is: conventional drill needle Φ0.30-6.2, the drill bit of the embodiment of the invention Φ 0.30-6.2; its processing parameters are: S145krpm, F90ipm, U1000ipm, H2000.

4) Comparative test four: wick comparison.

The wick data for Comparative Test 4 is shown in Table 4 below:

Research times\wick data (μm)\drill	Embodiment of the present invention	Conventional drill
New knife	18	62
Kenichi	20	70
Research II	25	75
Kenzo	26	78

It can be seen from Table 4 that, by analyzing the data, it is found that the burs of the embodiment of the present invention have a greater advantage in the wick than the conventional burs, and the wicks in the industry require less than 80 micrometers. The wick data during processing is much smaller than this value, which ensures high reliability of the PCB.

The above is only the preferred embodiment of the present invention, and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection of the present invention. Within the scope.

Claims

A PCB micro drill, comprising a drill body, and a main cutting edge or two main cutting edges or three main cutting edges, wherein the PCB micro drill further comprises a composite drill tip at one end of the drill body. The composite drill tip includes a first drill tip and a second drill tip, the second drill tip is disposed at an end of one end of the drill body, and the first drill tip starts at a top end of the second drill tip And extending outwardly in a direction parallel to a central axis of the drill body, the first drill tip includes a chisel edge that intersects the central axis of the drill body, and an inner main body that is in contact with the end of the chisel edge a cutting edge, and a first inner corner flank sandwiched between the inner major cutting edge and the chisel edge.
The PCB micro drill according to claim 1, wherein said first drill tip further comprises a second inner top portion on a side of said first inner top corner flank face and in contact with said chisel edge The corner flank face, the first inner top corner flank face and the second inner top corner flank face are obliquely intersected to form an inner apex angle.
The PCB micro drill according to claim 2, wherein the second drill tip comprises a first flank face outside the first inner corner flank face, and is formed on the first back blade A major cutting edge of one side edge of the face and connected to one end of the inner major cutting edge.
The PCB micro drill according to claim 3, wherein the second drill tip further comprises a second portion between the first flank face and the second inner apex flank face and intersecting with the two The flank, the contour of the second drill tip forms an outer apex angle.
The PCB micro drill according to claim 4, wherein said first flank face and said first apex angle flank face, and said second flank face and said second inside The apex angles are set at the same angle between the flank faces.
The PCB micro drill according to claim 5, wherein the first flank face and the outer wall of the drill body, and the second flank face and the outer wall of the drill body are identical Angle setting.
The PCB micro drill of claim 6 wherein said inner apex angle is less than said outer apex angle.
The PCB micro drill according to claim 7, wherein the inner apex angle is 60° or more and 130° or less, and the outer apex angle is 110° or more and 180° or less.
The PCB micro drill according to claim 2, wherein a distance between a bottom edge of the first inner corner flank and a bottom edge of the second inner corner flank is d 1 . the PCB micro-drill outer diameter d 2, and 10% ≤d 1 / d 2 ≤90 %.
The PCB micro drill according to claim 9, wherein the outer wall of the drill body is spirally provided with a spiral chip flute, and the chip flute starts from the first drill point and The axis of the drill body extends toward its trailing end.